Sleep Blog
Straight answers to the sleep questions people search for, each paired with a free tool. 203 articles.
Bedtimes & sleep cycles
Free tool: Sleep Calculator
- Is 2 Hours of Sleep Enough? For One Day, an Exam, or SchoolNo. Two hours is far short of the 7 adults need, but it usually beats staying up. Time it as one 90-minute cycle and don't drive on it.4 min read
- What Time Should I Go to Bed If I Wake Up at 11 AM?For an 11 AM wake-up, go to bed at 3:15 AM for 7.5 hours of sleep or 1:45 AM for 9 hours. Bedtimes for 11:30 AM too, and when waking at 11 is fine.5 min read
- What Time Should I Go to Bed If I Wake Up at 3 AM?For a 3 AM alarm, go to bed at 7:15 PM for 7.5 hours of sleep or 5:45 PM for 9 hours. Bedtimes for 3:15, 3:30 and 3:45 AM too, with the math shown.6 min read
- How to Sleep Better Camping: Warmth, Light and Timing (Sponsored)To sleep better camping, insulate from the ground, stay dry and warm, go to bed earlier with the sun, and expect a lighter first night. Times and tips inside.Sponsored · 5 min read
- How to Sleep in a Hotel Room When You Never Sleep Well Away (Sponsored)To sleep in a hotel room, expect a lighter first night, make the room dark, quiet and cool, and keep your usual bedtime and wake time. Here's the plan.Sponsored · 6 min read
- What Time Should I Wake Up If I Go to Sleep at 8 PM?If you go to sleep at 8 PM, wake up at 3:45 AM for 7.5 hours of sleep or 5:15 AM for 9 hours. Times for 8:30 PM too, and when 8 PM is too early.6 min read
- How Long Does It Take to Adjust to Daylight Saving Time?Most people adjust to fall back within about a week. Spring forward takes at least a week and can take longer. Timelines for adults, kids and babies.5 min read
- What Time Should I Go to Bed If I Wake Up at 10 AM?For a 10 AM wake-up, go to bed at 2:15 AM for 7.5 hours of sleep or 12:45 AM for 9 hours. Bedtimes for 10:30 AM too, and how to keep a late schedule healthy.5 min read
- What Time Should I Go to Bed If I Wake Up at 4 AM?For a 4 AM alarm, go to bed at 8:15 PM for 7.5 hours of sleep or 6:45 PM for 9 hours. Bedtimes for 4:30 and 4:45 AM too, with the math shown.5 min read
- What Time Should I Go to Bed If I Wake Up at 9 AM?For a 9 AM wake-up, go to bed at 1:15 AM for 7.5 hours of sleep or 11:45 PM for 9 hours. Bedtimes for 9:30 AM too, and when a late schedule works.4 min read
- How to Sleep When Stressed: What Works for a Racing, Anxious MindHandle worries before bed, not in it: a 15-minute worry session, a to-do list, slow breathing and getting up if you can't sleep. Plus when to see a doctor.4 min read
- What Time Should I Go to Bed If I Wake Up at 5 AM?For a 5 AM alarm, go to bed at 9:15 PM for 7.5 hours of sleep or 7:45 PM for 9 hours. Bedtimes for 5:30 and 5:45 AM too, with the math shown.5 min read
- Which US Cities Have the Darkest Winter Mornings? (2026 Data)Indianapolis has the darkest winter mornings of the 50 largest US cities: sunrise hits 8:06 AM in early January. See every city's latest sunrise.13 min read
- Do Nasal Strips Help You Sleep? Who They Work For (Sponsored)Nasal strips can make nose breathing easier, but trials show mixed sleep benefits and no effect on sleep apnea. Who they suit, who they don't, and why.Sponsored · 4 min read
- How to Choose a Mouth Tape: A Buyer's Checklist (Sponsored)Choose a mouth tape by checking skin-safety testing, PFAS testing, vent or no vent, beard grip, size, price per night and the guarantee. Here's the checklist.Sponsored · 4 min read
- How to Fall Asleep on Christmas Eve: A Plan for Excited Kids and Tired AdultsKeep the usual routine, set a no-earlier-than wake time and work back from it. Christmas Eve bedtimes for a 6:00 or 6:30 AM start, for kids and adults.5 min read
- Is It Bad to Sleep With Headphones or Earbuds In?Usually not, if the volume is low and they're comfortable. The real risks are loud all-night listening, ear soreness, earwax and cords. How to do it safely.4 min read
- Is It Bad to Sleep With Wet Hair? Colds, Breakage and What to DoIt won't give you a cold, since colds come from viruses. The real downsides are frizz and breakage. How to dry and time your shower for better sleep.4 min read
- Mouth Tape With CPAP: What the 2025 Study Found (Sponsored)A 2025 trial found mouth tape added about 52 minutes a day of CPAP use in mouth breathers. What it means, who should avoid it, and what to ask your doctor.Sponsored · 5 min read
- Does Sugar Keep You Awake? What the Research Actually ShowsSugar itself isn't a stimulant, and the kids' sugar high is mostly myth. But sugary diets are linked to lighter sleep, and many sweet drinks hide caffeine.4 min read
- Does Turkey Make You Sleepy? The Tryptophan Myth, CheckedNot really. Turkey has about as much tryptophan as chicken. The big meal, drinks, a short night and the afternoon dip are the likelier reasons you crash.5 min read
- What Is a Good Sleep Schedule? Example Schedules by Wake-Up TimeA good sleep schedule gives you 7 to 9 hours at the same times every day. Full sample schedules for workers, early risers, night owls and students.5 min read
- Why Am I So Tired in the Winter? The Body Clock Reasons and What HelpsWinter tiredness is mostly about light: later sunrises and dim indoor days weaken your body clock's morning signal. Why it happens and what helps.4 min read
- Fall Back 2026: When Clocks Change and How to Use the Extra HourUS clocks fall back at 2 AM on Sunday, Nov 1, 2026 (UK and EU: Oct 25). You gain an hour once, but your body still wakes early. Here's a 4-day plan.4 min read
- How to Wake Up at 6 AM (and Actually Stick With It)To wake up at 6 AM rested, go to bed at 10:15 PM. How to shift from a 7 or 8 AM wake-up, use morning light, and keep weekends from undoing it.5 min read
- Is It Bad to Sleep With the Lights On? What the Research ShowsProbably, if the light is bright. One night with room light on raised next-morning insulin resistance in a lab study. Here's what to do instead.4 min read
- What Time Should I Eat Dinner? Work Back From Your BedtimeEat dinner so you finish about 3 hours before bed. For a 10:15 PM bedtime and 6 AM alarm, that means done by 7:15 PM. See your time by wake-up.5 min read
- Is 7.5 Hours of Sleep Enough? Why 5 Full Cycles Often Feels Better Than 8For most adults, yes. 7.5 hours is inside the 7 to 9 hour range and equals exactly 5 sleep cycles. Who needs more, and bedtimes for 7.5 hours by wake time.5 min read
- How to Wake Up Refreshed: Cycle-Timed Alarms, Light and Enough SleepSleep at least 7 hours, set your alarm for the end of a sleep cycle, keep the same wake time and get light right away. Plus a cycle-timed alarm chart.4 min read
- How to Wake Up a Heavy Sleeper (Including Yourself)Time the alarm to the end of a sleep cycle, add light and a second alarm across the room, and fix short sleep. Plus when trouble waking is worth a doctor visit.4 min read
- How to Wake Up at 4 AM (and What Time to Go to Bed)To wake up at 4 AM with 7.5 hours of sleep, go to bed at 8:15 PM. How to make that bedtime realistic, and whether waking at 4 AM is healthy.5 min read
- Is 8 Hours of Sleep Enough? Why 8 Hours Can Still Leave You TiredFor most adults, yes. But 8 hours in bed isn't 8 hours asleep, and 8 hours isn't cycle-aligned. Why you may still feel tired, and what to check.4 min read
- What Time Do Most People Go to Bed? Average Bedtime DataThe most common bedtime is around 11 PM, with a 7 AM wake-up. How bedtime shifts with age, gender and weekends, and how to pick yours.4 min read
- What Time Should I Wake Up If I Go to Bed at 10 PM?If you go to bed at 10 PM, wake up at 5:45 AM for 7.5 hours of sleep or 7:15 AM for 9 hours. A 6 AM alarm gives you 7 hours 45 minutes.4 min read
- What Time Should I Wake Up If I Go to Bed at 2 AM?If you go to bed at 2 AM, wake up at 9:45 AM for 7.5 hours of sleep. With an earlier alarm, 8:15 AM (6 hours) or 6:45 AM (4.5 hours) is the least bad.4 min read
- What Time Should I Wake Up If I Go to Bed at 9 PM?If you go to bed at 9 PM, wake up at 4:45 AM for 7.5 hours of sleep or 6:15 AM for 9 hours. When 9 PM makes sense, and when it's too early.4 min read
- Do Sleep Calculators Work? How Accurate They Really AreSleep calculators reliably plan enough hours at a steady bedtime. Waking at the exact end of a cycle is an estimate you can tune in a week.4 min read
- How to Calculate Hours Slept (Even When You Cross Midnight)Hours slept = time in bed minus time to fall asleep and time awake. How to do the math across midnight, with worked examples and a free calculator.4 min read
- How to Calculate Your Sleep Cycle (Formula, Examples and Your Own Cycle Length)Wake time = bedtime + 15 min + cycles x 90 min. Here's the sleep calculator formula with worked examples, and how to estimate your own cycle length.5 min read
- REM Sleep Calculator: When to Wake Up (and What It Can't Tell You)No calculator can time your REM sleep exactly. What it can do is find cycle-end wake times: fall-asleep time + 90 min per cycle. Examples and limits.4 min read
- Sleep Regularity and Sleep Midpoint: How to Calculate ThemSleep midpoint is halfway between falling asleep and waking. Compare weekday and weekend midpoints to calculate social jet lag and check your sleep regularity.5 min read
- What Time Should I Go to Bed to Get 8 Hours of Sleep?For 8 hours of sleep, go to bed 8 hours 15 minutes before your alarm, for example 10:15 PM for a 6:30 AM wake-up. Chart for 7, 8 and 9 hours.4 min read
- How Long Before Bed Is It OK to Work Out?Finish a hard workout at least 1 hour before bed, and 2 or more hours is safer. Moderate evening exercise generally doesn't hurt sleep.4 min read
- How Long Before Bed Should You Eat? The 3-Hour Rule, ExplainedFinish a full meal about 3 hours before bed, and at least 2 hours if you get heartburn. A small snack closer to bedtime is usually fine.4 min read
- How Long Before Bed Should You Stop Drinking Water?Ease off fluids about 2 hours before bed if you wake up to pee, and cut caffeine and alcohol earlier. When night urination is worth a doctor visit.4 min read
- How to Fix Your Sleep Schedule Fast (1-Day, 3-Day and 1-Week Plans)The fastest fix is to set your alarm for your target wake-up time tomorrow and hold it. One day works but hurts; 3 days to a week is easier.5 min read
- How to Wake Up Without an Alarm (What It Actually Takes)Get enough sleep, keep the same wake-up time every day, and get morning light. Most people need a few weeks before their body clock takes over.4 min read
- Is It Better to Sleep at 10 or 11 PM?Either can be healthy. Pick 10 PM if your alarm is around 5:45 AM and 11 PM if it's around 6:45 AM. Sleep before midnight doesn't count double.4 min read
- What Time Should I Wake Up If I Go to Bed at 1 AM?If you go to bed at 1 AM, wake up at 8:45 AM for 7.5 hours of sleep, or 7:15 AM for 6 hours on a short night. See how many hours each alarm gives you.4 min read
- What Time Should I Wake Up If I Go to Bed at 3 AM?If you go to bed at 3 AM, wake up at 10:45 AM for 7.5 hours. With a normal alarm, 7:45 AM (3 cycles) or 6:15 AM (2 cycles) is the least bad option.4 min read
- How Long Before Bed Should You Stop Drinking Alcohol?Alcohol mainly disrupts the second half of the night. Here's a rough timing guide by number of drinks, and why fewer drinks beats better timing.4 min read
- How to Reset Your Sleep Schedule After VacationBack from a week of late nights? Move your wake-up time 30 to 60 minutes earlier each day, get morning light, and you can be back on schedule in 4 to 7 days.4 min read
- How Many Sleep Cycles Do You Need a Night?Most adults need 5 sleep cycles a night. Here's what happens in each cycle, why the last ones matter, and how to plan your night around them.3 min read
- How to Wake Up at 5 AM (Without Feeling Awful)The bedtime you need for a 5 AM alarm, how to shift your schedule without wrecking your week, and the evening habits that make early mornings easier.3 min read
- What Time Should I Go to Bed? A Bedtime Chart for Every Wake-Up TimeFind your ideal bedtime for any wake-up time from 4 AM to 10 AM, based on 90-minute sleep cycles. One chart, no math.3 min read
- 7 vs 8 Hours of Sleep: Which Is Better?Both are within the healthy range for adults. 8 hours gives more margin, but 7.5 hours often feels better because it ends on a full sleep cycle.3 min read
- A Bedtime Routine for Adults: The 60-Minute Wind-Down That Actually WorksA simple 60-minute bedtime routine for adults, minute by minute, with the reasoning behind each step and how to fit it into a busy night.4 min read
- Are You a Night Owl or an Early Bird? Chronotypes, and Whether You Can Change YoursYour chronotype is partly genetic and shifts with age. Here's how to tell which you are, how much you can change it, and how to work with it.4 min read
- Do Sleep Cycle Alarm Apps Work? An Honest Look at Smart AlarmsSmart alarms promise to wake you in light sleep. Here's how phones and wearables guess your sleep stage, how accurate they are, and what works instead.4 min read
- How Long Does It Take to Fall Asleep? What's Normal, Too Fast and Too SlowMost healthy adults fall asleep in about 10 to 20 minutes. Falling asleep in under 5 minutes, or regularly over 30, can be a sign something's off.3 min read
- How to Go to Bed Earlier (and Actually Fall Asleep)Move your bedtime 15 minutes earlier every few days, fix your wake-up time first, and get morning light. A step-by-step plan that works.4 min read
- How to Sleep Before a Race: The Two-Nights-Before Rule and a Race-Eve PlanWhy the night two days before your marathon matters most, what bedtime to aim for before an early start, and what to do if nerves keep you up.4 min read
- How to Sleep Before an Exam (and Why the Week Before Matters More)How to sleep well before an exam: the bedtime to aim for, a night-before plan, and why your sleep over the whole week matters more than one night.4 min read
- How to Stop Hitting Snooze (and Actually Get Up)Set one alarm for the time you really get up, put it across the room, and fix the bedtime that's leaving you short. A step-by-step plan.3 min read
- What Is a Good Bedtime for Adults?For most adults with a 6 to 7 AM alarm, a good bedtime is between about 10 and 11:15 PM. Here's how to find yours and the latest you should go.3 min read
- What Is REM Sleep? How Much You Need and What Cuts It ShortREM is the dreaming stage of sleep. Most adults get about 1.5 to 2 hours a night, mostly in the early morning. Here's what cuts it short.4 min read
- What Is the Best Time to Sleep and Wake Up?There's no single best time. The best sleep window gives you 7 to 9 hours, fits your body clock and stays the same every day. Here's how to find yours.4 min read
- What Time Should I Go to Bed If I Wake Up at 6 AM?For a 6 AM alarm, go to bed at 10:15 PM for 7.5 hours of sleep or 8:45 PM for 9 hours. Exact times adjusted for how fast you fall asleep.4 min read
- What Time Should I Go to Bed If I Wake Up at 7 AM?For a 7 AM alarm, go to bed at 11:15 PM for 7.5 hours of sleep or 9:45 PM for 9 hours. Plus an evening timeline that makes it realistic.4 min read
- What Time Should I Go to Bed If I Wake Up at 8 AM?For an 8 AM wake-up, go to bed at 12:15 AM for 7.5 hours of sleep or 10:45 PM for 9 hours. Tips for night owls and remote workers.3 min read
- What Time Should I Wake Up If I Go to Bed at 11 PM?If you go to bed at 11 PM, wake up at 6:45 AM for 7.5 hours of sleep or 8:15 AM for 9 hours. See how your usual alarm lines up with your cycles.3 min read
- What Time Should I Wake Up If I Go to Bed at Midnight?If you go to bed at midnight, wake up at 7:45 AM for 7.5 hours of sleep or 9:15 AM for 9 hours. What to do when your alarm is earlier.3 min read
- What Time Should I Wake Up? Chart by BedtimeFind the best wake-up time for any bedtime from 8 PM to 2 AM, based on 90-minute sleep cycles. For most adults, 5 cycles (7.5 hours) is the target.4 min read
- Why Do I Wake Up With a Dry Mouth? Common Causes and What HelpsWaking up with a dry mouth usually comes from mouth breathing, dry air, alcohol or medications. Here's how to find your cause and when to see a doctor.4 min read
Naps
Free tool: Nap Calculator
- Is It Bad to Sleep After a Workout? Napping After Exercise, ExplainedNo. Sleeping or napping after a workout is fine and may help you feel recovered. Keep naps to 20 or 90 minutes and finish them by mid-afternoon.4 min read
- How to Stay Awake While Driving (and When to Stop Trying)Pull over somewhere safe, have caffeine and take a 20-minute nap. Window-down and loud-radio tricks don't work reliably. Warning signs and a road-trip plan.5 min read
- Why Do I Feel Worse After a Nap? Sleep Inertia and How to Wake Up ClearYou likely woke from deep sleep. That groggy feeling is sleep inertia, and it usually fades within 30 minutes. How to nap and wake up without it.4 min read
- Why Do I Get Tired After Eating? Causes, Fixes and When to WorryMostly your body clock's afternoon dip, made worse by big meals and short sleep. Whether it's bad to sleep after eating, how long to wait, and red flags.4 min read
- How to Sleep in Your Car Safely (Road Trips, Rest Stops, Overnights)Pull over somewhere safe, lock up, crack a window, never run the engine in an enclosed space, and set an alarm. How to sleep in your car, step by step.4 min read
- Can't Sleep at Night After a Nap? How to Fix ItA late or long nap drains the sleep pressure you need at bedtime. How to fall asleep tonight, and the latest time to finish a nap for your bedtime.4 min read
- How Long Should You Nap Before Studying?Nap 10 to 20 minutes and give yourself about 10 minutes to wake up before you study. If you have 2 hours, a full 90-minute nap can help too.4 min read
- Is It Better to Sleep 1 Hour or Stay Up All Night?Short on time before an early flight or exam? Here's when a short sleep beats staying up, how long to sleep, and how to time the alarm.3 min read
- How to Nap at Work, in Your Car or on a BreakKeep it to 10 to 20 minutes, nap on your own break time, and time it for early afternoon. How to nap at work, in a car or on a shift, safely.4 min read
- Is a 90-Minute Nap Too Long?Not usually. A 90-minute nap covers one full sleep cycle, so you tend to wake refreshed. Take it early in the afternoon so it doesn't hurt tonight's sleep.3 min read
- What Is the Best Time to Take a Nap?The best time to nap is early afternoon, roughly 1 to 3 PM for a 7 AM riser, during the natural post-lunch dip. Find your nap window by wake-up time.4 min read
Sleep debt & short sleep
Free tool: Sleep Debt Calculator
- Can Your Body Adapt to Less Sleep? What Adapts, What Doesn'tNot really. You get used to feeling tired, but in lab studies performance kept falling on short sleep. What adapts, what doesn't, and how to tell if you're short.4 min read
- Is 5.5 Hours of Sleep Enough? The Mid-Cycle Problem and the Weekly CostNo, not for adults. 5.5 hours is 1.5 hours under the 7-hour minimum and ends mid-cycle. What 4.5 or 6 hours would feel like instead, and a plan to fix it.5 min read
- Is 6.5 Hours of Sleep Enough? The Cycle Math and the Weekly ShortfallFor most adults, no: 6.5 hours is 30 minutes under the 7-hour minimum, and your alarm lands mid-cycle. Here's what it costs per week and how to fix it.5 min read
- How to Stay Awake at Work When You're ExhaustedGet bright light, move for a few minutes, time caffeine early and take a short nap on your break if allowed. What works, what doesn't, and when to see a doctor.5 min read
- Is 3 Hours of Sleep Enough? One Night, Every Night, and What to Do NextNo. Three hours is less than half what adults need. It beats an all-nighter, but it's unsafe to drive on. What to do with the hours you have.5 min read
- Is 7 Hours of Sleep Enough? The Guideline, the Cycle Math and Who It SuitsYes for many adults: 7 hours is the minimum experts recommend. But it's the floor, not the target, and 7.5 hours often feels better. Here's why.5 min read
- Is It Bad to Sleep All Day? When It's Recovery and When It's a SignSleeping all day once after a rough week is usually recovery sleep. If it keeps happening or you're still tired, it can be a sign worth checking.4 min read
- How to Calculate Sleep Debt (With a Worked Weekly Example)Sleep debt = sleep you need x 7 minus sleep you got this week. A worked example, how to count weekend catch-up, and how to plan recovery.4 min read
- Is 4 Hours of Sleep Enough? One Night, Every Night, and What to DoNo. Four hours is about half of what adults need. You can get through one night, but it's not safe to drive on and not something to repeat.4 min read
- How Long Can You Go Without Sleep? What Research ShowsPerformance starts slipping after about 16 hours awake. By 24 hours it resembles being over the legal driving limit. Here's what happens, and how to recover.4 min read
- Is 6 Hours of Sleep Enough? What the Research Actually ShowsSix hours feels fine to a lot of people. Research says it isn't, and that you're the last to notice. Here's what 6 hours does and how to get more.3 min read
- 12 Signs You Are Sleep Deprived (Even If You Feel Fine)Needing an alarm, falling asleep instantly, weekend lie-ins and afternoon crashes are common signs of sleep deprivation. Here's the checklist and what to do.4 min read
- How to Recover From an All-Nighter: The Next 24 to 48 HoursPulled an all-nighter? Get through the next day safely, then use one early night and a fixed wake-up time to get back to normal within a day or two.4 min read
- Is 5 Hours of Sleep Enough? What It Does to You, and How to Get Through the DayNo. Five hours is about 2 hours short of what adults need, and effects build every night. Here's how to time a short night and recover from it.4 min read
- Is It Bad to Sleep In on Weekends? How Much Is Too MuchSleeping in up to about an hour on weekends is fine for most people. Much more than that shifts your body clock and makes Monday harder.4 min read
Caffeine
Free tool: Caffeine Cutoff Calculator
- How Much Caffeine Is in a Caramel Macchiato? Starbucks, Iced and Your CutoffA grande Starbucks Caramel Macchiato has 150 mg of caffeine, hot or iced. An espresso macchiato is different: a doppio has 150 mg in under 2 oz.5 min read
- How Much Caffeine Is in a Flat White? Starbucks, vs Latte and Your CutoffA flat white is usually built on a double shot, about 126 mg of caffeine. A tall Starbucks Flat White has 130 mg. See the latest time to drink one.5 min read
- How Much Caffeine Is in a Mocha? Starbucks, Peppermint Mocha and Your CutoffA mocha has about 63 mg of caffeine per espresso shot plus a little from the chocolate. A grande Starbucks Caffè Mocha has 175 mg. See your cutoff.5 min read
- How Much Caffeine Is in Black Tea? Per Cup, Per Bag, and vs CoffeeAbout 47 mg in an 8 oz cup of brewed black tea, half a cup of coffee. Bag, mug and green tea comparisons, plus the latest time to drink it before bed.4 min read
- How Much Caffeine Is in Instant Coffee? Per Teaspoon, Packet and CupAbout 31 mg per level teaspoon of powder and 62 mg in an 8 oz cup, per USDA data. Packet, tablespoon and rounded spoon amounts, plus your latest cup.5 min read
- How Much Caffeine Is in Pike Place? Grande, K-Cups and Your CutoffA grande Starbucks Pike Place Roast has 315 to 390 mg of caffeine, close to the FDA's 400 mg a day in one cup and more than a grande Americano.5 min read
- How Much Caffeine Is in a Cappuccino? Starbucks, vs Coffee and Your CutoffA cappuccino has about 63 mg of caffeine per espresso shot, so a double is about 126 mg. A grande Starbucks Cappuccino has 150 mg. See your latest cup.4 min read
- How Much Caffeine Is in a K-Cup? Pod, Brew Size and Your CutoffA regular K-Cup pod has roughly 95 mg of caffeine, about the same as an 8 oz brewed coffee, and a bigger brew size doesn't add any. See your latest cup.5 min read
- How Much Caffeine Is in a Latte? Starbucks, vs Coffee and Your CutoffA latte has about 63 mg of caffeine per espresso shot, so a two-shot latte has about 126 mg. A grande Starbucks Caffè Latte has 150 mg. See your cutoff.5 min read
- How Much Caffeine Is in an Americano? Starbucks Grande, vs Coffee and Your CutoffAn Americano has about 63 mg of caffeine per espresso shot, so two shots is about 126 mg. A grande Starbucks Caffè Americano has 225 mg. See your cutoff.5 min read
- How Much Caffeine Is in Hot Chocolate? Mix, Homemade and StarbucksA cup of hot chocolate has about 4 to 5 mg of caffeine, per USDA data, less than decaf coffee. A grande Starbucks Hot Chocolate has 25 mg.5 min read
- How Much Caffeine Is in Matcha? Powder, Latte and Starbucks vs CoffeeMatcha has about 16 mg of caffeine per gram of powder, so a 2 g serving has about 32 mg. A grande Starbucks matcha latte has 65 mg. See your latest cup.5 min read
- How Much Caffeine Is in Pepsi? Can, 20 oz, Zero Sugar and DietA 12 oz can of Pepsi or Pepsi Zero Sugar has 38 mg of caffeine and a 20 oz bottle has 63 mg. Diet Pepsi has 35 mg. See your latest Pepsi before bed.6 min read
- How Much Caffeine Is in a 5-hour Energy Shot? Regular and Extra StrengthA Regular Strength 5-hour Energy shot has 200 mg of caffeine and Extra Strength has 230 mg, in a 1.93 oz bottle. See what's left at bedtime.4 min read
- How Much Caffeine Is in a Dunkin' Iced Coffee? Small, Medium and LargeDunkin' lists about 196 mg of caffeine in a small iced coffee, 294 mg in a medium and 392 mg in a large. See what's left at bedtime and your cutoff.5 min read
- How Much Caffeine Is in Alani Nu? Energy Drink, Witch's Brew and Mini CansA 12 oz Alani Nu energy drink has 200 mg of caffeine, Witch's Brew included. The 8.4 oz mini has 100 mg. See what's left at bedtime and your cutoff.4 min read
- How Much Caffeine Is in Bang Energy? 300 mg a Can, Plus Bedtime MathA 16 oz can of Bang Energy has 300 mg of caffeine in every flavor, about three cups of coffee. See what's left at bedtime and your latest can.4 min read
- How Much Caffeine Is in C4 Energy? Performance, Ultimate and Smart Energy CansA 16 oz C4 Performance Energy has 200 mg of caffeine, C4 Ultimate has 300 mg and C4 Smart Energy has 200 mg per 12 oz. See your bedtime cutoff.4 min read
- How Much Caffeine Is in Ghost Energy? Full Can and Half Can, Plus Bedtime MathA 16 oz Ghost Energy has 200 mg of caffeine and the 8.4 oz half can has 100 mg. Every Ghost Energy is zero sugar. See your bedtime cutoff.4 min read
- How Much Caffeine Is in Prime Energy? (Not the Same as Prime Hydration)A 16 oz can of Prime Energy has 200 mg of caffeine and is labeled for ages 18+. Prime Hydration bottles are caffeine-free. See your bedtime cutoff.4 min read
- How Much Caffeine Is in a Frappuccino? Coffee vs Crème, Bottled, and Your CutoffA grande Coffee Frappuccino has about 95 mg of caffeine. Most Crème Frappuccinos have none, and a 13.7 oz bottled Coffee Frappuccino has 110 mg.5 min read
- How Much Caffeine Is in a Starbucks Refresher? Tall to Trenta, Plus Energy RefreshersA grande Starbucks Refresher has about 50 mg of caffeine and a trenta about 100 mg. Energy Refreshers have 100 to 175 mg. See your bedtime cutoff.6 min read
- How Much Caffeine Is in Sweet Tea? Home-Brewed, Bottled, Chick-fil-A and McDonald'sAn 8 oz glass of brewed black tea, the base of sweet tea, has about 47 mg of caffeine, half a cup of coffee. Bottled, restaurant and bedtime numbers.5 min read
- How Much Caffeine Is in a Pumpkin Spice Latte? Short to Venti, Plus Your CutoffA grande Starbucks Pumpkin Spice Latte has about 150 mg of caffeine and a tall has 75 mg. See how it compares to coffee and your latest PSL before bed.5 min read
- How Much Caffeine Is in Mountain Dew? Can, 20 oz, Zero Sugar, Baja Blast and KickstartA 12 oz can of Mountain Dew has 54 mg of caffeine and a 20 oz bottle has 91 mg. Zero Sugar has more. See your latest Dew before bed.6 min read
- Monster vs Red Bull Caffeine: Which Has More, and Which Is Easier on Sleep?A 16 oz Monster has 160 mg of caffeine and a 16 oz Red Bull has 151 mg. Per ounce they're nearly tied. See the bedtime math and your latest can.6 min read
- How Much Caffeine Is in Monster? Original, Zero Sugar, Ultra, Rehab and JavaA 16 oz Monster has 160 mg of caffeine, Zero Ultra has 150 mg and Java Monster has 200 mg per 15 oz. See what's left at bedtime and your latest can.5 min read
- How Much Caffeine Is in Red Bull? Every Can Size, Plus Bedtime MathAn 8.4 oz (250 ml) Red Bull has 80 mg of caffeine, a 12 oz has 114 mg and a 16 oz has 151 mg. See how much is left at bedtime and your latest can.5 min read
- How Much Caffeine Is in a Chai Latte? Café, Homemade, Dirty Chai and Your CutoffA 16 oz chai latte has about 40 to 55 mg of caffeine, roughly half a cup of coffee. Add an espresso shot for a dirty chai and it jumps past 100 mg.4 min read
- How Much Caffeine Is in Yerba Mate? Tea Bags, Gourds, Cans and Your CutoffYerba mate releases about 18 mg of caffeine per gram of leaf, so a 2 g tea bag gives about 36 mg. Cans run 20 to 30 mg per 100 mL. Bedtime cutoffs inside.5 min read
- How Much Caffeine Is in Cold Brew? Concentrate, Iced Coffee and Your CutoffA 16 oz cold brew made from concentrate can have 230 to 290 mg of caffeine. Iced coffee has about 150 mg in 16 oz. Your latest cup before bed.5 min read
- How Much Caffeine Is in Coke and Diet Coke? (Plus Other Sodas)A 12 oz can of Coke or Coke Zero has 34 mg of caffeine and Diet Coke has 46 mg. See what an evening can leaves at bedtime and your latest can.5 min read
- How Much Caffeine Is in Dark Chocolate? (And Will It Keep You Up?)An ounce of 70-85% dark chocolate has about 23 mg of caffeine, per USDA data, a quarter of a coffee. See what an evening dessert leaves at bedtime.5 min read
- Does Tea Have More Caffeine Than Coffee? Cup by Cup, With Bedtime MathNo. Per cup, coffee has about 95 mg of caffeine and tea about 28 to 47 mg. Black, green, white and matcha compared, plus how long each stays in you.4 min read
- How Much Caffeine Is in a Shot of Espresso? Single, Double, Latte and Your CutoffA 1 oz shot of espresso has about 63 mg of caffeine, a double about 126 mg. Why it's stronger than coffee per ounce, and your latest shot before bed.5 min read
- Can You Drink Coffee at Night? How Much Is Left at BedtimeYou can, but a regular coffee at 6 PM still leaves about 48 mg in you at 11 PM. See how much is left by drink and time, plus the night-shift and decaf options.4 min read
- How Long Does Celsius Last? Caffeine Hour by Hour, and When to StopA 200 mg can of Celsius takes about 15 hours to drop below 25 mg on average. See the hour-by-hour chart and the latest time to drink one for your bedtime.5 min read
- Why Does Caffeine Make Me Tired? 6 Reasons Coffee BackfiresCaffeine makes you sleepy mostly because of tolerance, withdrawal, sleep debt it was masking, and sugar in the drink. Here's what the evidence shows, and the fixes.5 min read
- How Long Does Pre-Workout Last? Onset, Peak and How Long the Caffeine Stays in YouThe boost kicks in within 30 to 60 minutes and fades in a few hours, but a 200 mg scoop takes about 15 hours to drop below 25 mg. Tables for 150 to 300 mg.4 min read
- How Much Caffeine Is Too Much? The 400 mg Limit in Real Drinks, and the Lower Limit for SleepAbout 400 mg a day for most healthy adults, roughly four 8 oz coffees. For sleep the limit is lower and depends on the time. Tables by drink and hour.4 min read
- How Long Does Caffeine Take to Kick In?Caffeine is absorbed fast and blood levels can peak in about 30 minutes, so drink it 30 to 45 minutes before you need to be sharp. Plus coffee-nap timing.4 min read
- How Much Caffeine Is in Your Drink? A Chart, Plus Your Cutoff TimeCaffeine in coffee, espresso, tea, soda and energy drinks side by side, plus the latest time to drink each one for a 10:30 PM bedtime.3 min read
- Does Green Tea Keep You Awake? Caffeine, L-Theanine and TimingOne cup of green tea has about 28 mg of caffeine, so it rarely wrecks sleep, but several cups or matcha can. Here's the latest time to drink it.3 min read
- Drank Coffee Too Late? How to Fall Asleep AnywayNothing flushes caffeine out faster, so the honest fix is to wait it out well. Here's how much is left, when it clears, and what actually helps tonight.3 min read
- Energy Drinks and Sleep: How Late Is Too Late?A 16 oz energy drink can hold about 160 mg of caffeine, enough to affect sleep even from a mid-morning can. See cutoff times by can size.4 min read
- How Long Does Caffeine Last? An Hour-by-Hour TimelineCaffeine has an average half-life of about 5 hours, so half a morning coffee is still in you at lunch. See the hour-by-hour timeline for a 95 mg cup.4 min read
- Is Decaf Coffee OK Before Bed? How Much Caffeine Is LeftDecaf still has about 2 to 15 mg of caffeine per 8 oz cup. One cup after dinner is fine for most people; several cups or decaf espressos add up.3 min read
- Pre-Workout Before Bed: Can You Train Late and Still Sleep?A stimulant pre-workout with 200 mg of caffeine at 6 PM still leaves about 107 mg at a 10:30 PM bedtime. Here are cutoff times and stim-free options.3 min read
Sleep by age
Free tool: Sleep Needs by Age
- What Time Should a 15-Year-Old Go to Bed? School Nights, Weekends and SummerA 15-year-old who wakes at 6:30 AM should go to bed around 9:15 PM, and by 10:15 PM at the latest. Bedtimes for school nights, weekends and summer.5 min read
- What Time Should a 17-Year-Old Go to Bed? School Nights, Weekends and JobsA 17-year-old who wakes at 6:30 AM should go to bed around 9:15 PM, and by 10:15 PM at the latest. Bedtimes for school nights, weekends, jobs and driving.5 min read
- What Time Should a 6-Year-Old Go to Bed? School Nights, Weekends and SummerA 6-year-old who wakes at 7 AM should go to bed around 8:15 PM, and by 9:45 PM at the latest. Bedtimes for school nights, weekends and summer.5 min read
- What Time Should a 13-Year-Old Go to Bed? School Nights, Weekends and SummerA 13-year-old who wakes at 6:30 AM should go to bed around 9:15 PM, and by 10:15 PM at the latest. Bedtimes for school nights, weekends and summer.5 min read
- What Time Should a 4-Year-Old Go to Bed? With a Nap, Without, and on School NightsA 4-year-old with no nap who wakes at 7 AM should go to bed around 7:15 PM. With a 1-hour nap, about 8:15 PM. Charts by wake-up time and nap.5 min read
- What Time Should an 11-Year-Old Go to Bed? School Nights, Weekends and SummerAn 11-year-old who wakes at 7 AM should go to bed around 8:45 PM, and by 9:45 PM at the latest. Up at 6 AM? Bed around 7:45 PM. Full charts inside.5 min read
- What Time Should an 8-Year-Old Go to Bed? School Nights, Weekends and SummerAn 8-year-old who wakes at 7 AM should go to bed around 8:15 PM, and by 9:45 PM at the latest. Bedtimes for school nights, weekends and summer.5 min read
- What Time Should a 1-Year-Old Go to Bed? With Two Naps or OneA 1-year-old who wakes at 7 AM and naps 1.5 hours should go to bed around 7:15 PM. Bedtime charts by wake-up time and nap length, for two naps or one.5 min read
- What Time Should a 16-Year-Old Go to Bed? School Nights, Weekends and SummerA 16-year-old who wakes at 6:30 AM should go to bed around 9:15 PM, and by 10:15 PM at the latest. Bedtimes for school nights, weekends, summer, jobs and sports.5 min read
- What Time Should a 14-Year-Old Go to Bed? School Nights, Weekends and SummerA 14-year-old who wakes at 6:30 AM should go to bed around 9:15 PM, and by 10:15 PM at the latest. Bedtimes for school nights, weekends and summer.5 min read
- What Time Should a 2-Year-Old Go to Bed? With a Nap and WithoutA 2-year-old who wakes at 7 AM and naps 1.5 hours should go to bed around 7:45 PM. Without a nap, about 6:15 PM. Charts by wake-up time and nap.4 min read
- What Time Should a 9-Year-Old Go to Bed? School Nights, Weekends and SummerA 9-year-old who wakes at 7 AM should go to bed around 8:15 PM, and by 9:45 PM at the latest. Bedtimes for school nights, weekends and summer.4 min read
- Deep Sleep Calculator: How Many Minutes of Deep Sleep You GetTurn your hours of sleep into minutes of deep sleep. Most adults get 15 to 20% deep sleep, about 1 to 1.5 hours a night. Table by age and hours slept.5 min read
- What Time Should a 10-Year-Old Go to Bed? School Nights, Weekends and SummerA 10-year-old who wakes at 7 AM should go to bed around 8:45 PM, and by 9:45 PM at the latest. Bedtimes for school nights, weekends and summer.4 min read
- What Time Should a 3-Year-Old Go to Bed? With a Nap and WithoutA 3-year-old who naps 1.5 hours and wakes at 7 AM should go to bed around 8:15 PM. Without a nap, about 6:45 PM. Charts by wake-up time and nap.4 min read
- Does Sleep Make You Taller? What Sleep Can and Can't Do for HeightNot beyond your genes. Sleep doesn't add height, but growth hormone peaks in deep sleep and kids and teens need 8 to 12 hours. What sleep really does.4 min read
- Bedtime Routine for Kids: Step by Step, With Start Times by AgeA good bedtime routine for kids is the same 4 or 5 calm steps every night, started 30 to 45 minutes before lights out. Steps and start times by age.4 min read
- What Time Should a 12-Year-Old Go to Bed? Bedtimes for Ages 10 to 12A 12-year-old needs 9 to 12 hours of sleep: for a 7 AM wake-up, bed around 8:45 PM and by 9:45 at the latest. Bedtimes for ages 10, 11 and 12.4 min read
- What Time Should a 5-Year-Old Go to Bed? Bedtimes for Ages 3 to 5A 5-year-old with no nap who wakes at 7 AM should go to bed around 7:45 PM. Bedtimes for ages 3, 4 and 5 by wake time, and how naps change them.4 min read
- What Time Should a 7-Year-Old Go to Bed? Bedtimes for Ages 6 to 9A 7-year-old who wakes at 7 AM should go to bed between about 7:45 and 8:15 PM. Bedtimes for ages 6, 7, 8 and 9 by wake-up time, plus summer tips.4 min read
- What Time Should a Teenager Go to Bed? Bedtimes for Ages 13 to 17Most teens should be asleep by 9:15 to 10:15 PM for a 6:30 AM alarm. Bedtimes for ages 13 to 17 by wake-up time, plus weekends, phones and school starts.5 min read
- How Much Sleep Do You Need When You're Sick?When you're sick, aim for at least your normal 7 to 9 hours, plus extra rest or naps if your body asks for it. What research says and when to see a doctor.4 min read
- How to Calculate How Much Sleep You Need (A Simple Self-Test)Start with your age range (7 to 9 hours for most adults), then find your own number by averaging your sleep on the last nights of a week with no alarm.4 min read
- Sleep Calculator by Age and Gender: Do Women Need More Sleep?Adults 18 to 64 need 7 to 9 hours and adults 65+ need 7 to 8, for men and women alike. How to calculate your bedtime, and what sex differences exist.4 min read
- What Time Should Kids Go to Bed? Bedtime Chart by AgeA simple bedtime chart for kids and teens by wake-up time, based on how much sleep children need at each age, plus tips for making bedtime stick.3 min read
- How Much Sleep Do Athletes Need? What the Research SaysAthletes need at least 7 to 9 hours, and many do better with more. What sleep extension studies found, and bedtimes for 7.5, 9 or 10 hours in bed.4 min read
- How Much Sleep Do College Students Need? (And How to Get It in a Dorm)College students need 7 to 9 hours of sleep a night. Here's why most fall short, what all-nighters cost you, and how to sleep better in a dorm.3 min read
- How Much Sleep Do Older Adults Need? What Changes After 65Adults over 65 need about 7 to 8 hours of sleep. Here's how sleep changes with age, when naps help, and which sleep problems are worth a doctor's visit.4 min read
- How Much Sleep Do Teenagers Need? Hours, Bedtimes and Why Teens Stay Up LateTeens need 8 to 10 hours of sleep a night. Here's why their body clock runs late, and a bedtime table for every common school wake-up time.4 min read
- How Much Sleep Does a Toddler Need? Naps, Bedtimes and Sample SchedulesToddlers aged 1 to 2 need 11 to 14 hours of sleep a day, naps included. Sample schedules, when naps usually drop, and typical bedtime ranges.4 min read
Sleep quality
Free tool: Sleep Efficiency Calculator
- What Is a Good Sleep Score? Apple Watch, Garmin and Oura Compared (Sponsored)A good sleep score is about 80 or higher on most devices: 81+ on Apple Watch, 80+ on Garmin, 70+ on Oura (85+ optimal). Bands compared, plus what to check.Sponsored · 5 min read
- How to Fall Asleep When You're Not Tired (Without Forcing It)Don't force it. Wind down in dim light, get up if you're awake after about 20 minutes, and fix the nap, caffeine or wake time that left you wired.4 min read
- How to Stop Oversleeping: A 7-Step Plan That WorksKeep one wake time every day, get enough sleep on weeknights, put the alarm across the room and get light fast. Plus when oversleeping needs a doctor.4 min read
- How to Sleep Longer: 9 Evidence-Based Ways to Stay AsleepTo sleep longer, fix your wake-up time, get morning light, cut caffeine 6+ hours and alcohol hours before bed, and leave bed if you lie awake.4 min read
- How to Calculate Sleep Efficiency (Plus Sleep Latency and WASO)Sleep efficiency = time asleep / time in bed x 100. Worked examples, how to calculate sleep latency and WASO, and what percentage counts as good.4 min read
- Is It Bad to Lie in Bed Awake? The 20-Minute Rule ExplainedLying awake for a long time can train your brain to link bed with being awake. How the 20-minute rule works and what to do when you get up.3 min read
- Time in Bed vs Time Asleep: Why 8 Hours in Bed Isn't 8 Hours of SleepTime in bed includes falling asleep and waking in the night, so it's always more than your sleep. How to work out the gap and what's normal.4 min read
- What Is Sleep Restriction Therapy? How It Works in CBT-ISleep restriction therapy treats insomnia by matching time in bed to the sleep you actually get. How it works and why to do it with a clinician.4 min read
Shift work
Free tool: Shift Work Sleep Calculator
- Is It Better to Sleep at Night or During the Day?For most people, night is better. Your body clock is set up for night sleep, and day sleep tends to be shorter. How to make day sleep work when you must.4 min read
- How to Stay Awake on Night Shift: Naps, Light, Caffeine Timing and the 4 AM DipNap before the shift, keep caffeine to the first half of the night, work in bright light and plan for the early-morning low. Computed cutoffs for an 11 PM start.5 min read
- Third Shift Sleep Schedule: Sleep Times for 11 PM-7 AM and 10 PM-6 AM ShiftsOn an 11 PM to 7 AM shift with a 30-minute commute, sleep 8:00 AM to 3:45 PM. Computed graveyard shift plans by commute, a split-sleep option and days off.5 min read
- Rotating Shift Sleep Schedule: Sleep Times for Day, Evening and Night RotationsSleep 10 PM to 5:45 AM on days, midnight to 7:45 AM on evenings, 8 AM to 3:45 PM on nights. Forward vs. backward rotation and how to handle switch days.4 min read
- Second Shift Sleep Schedule: Sleep Times for 3-11 PM and 4 PM-12 AM ShiftsOn a 3 to 11 PM shift with a 30-minute commute, sleep from midnight to 7:45 AM. Computed plans for common second-shift hours, caffeine cutoffs and days off.5 min read
- 12-Hour Shift Sleep Schedule: Day and Night Shift TimingsSleep times for 7 AM to 7 PM and 7 PM to 7 AM shifts at every commute length, plus what to do with only 10 hours between shifts.5 min read
- How to Sleep During the Day After a Night ShiftGo to bed soon after you get home, in a room that's truly dark and quiet. A worked day-sleep schedule for a 7 PM to 7 AM shift, plus setup tips.4 min read
- How to Switch From Night Shift to Days (and Back Again)Take a short 3 to 4.5 hour sleep after your last night shift, then stay up until a normal bedtime. How to flip back, plus when not to flip fully.4 min read
Jet lag & travel
Free tool: Jet Lag Calculator
- How to Sleep on a Red Eye Flight: Timing Before, During and After (Sponsored)Eat before you board, stop coffee about 9.5 hours before you plan to sleep, sleep right after takeoff, then take one short nap the next day.Sponsored · 6 min read
- When to Sleep on a Plane to Avoid Jet Lag (With Timing Tables)Sleep on a plane when it's night at your destination, stay awake when it's day there. Plus seat choice, caffeine and alcohol timing, and sleep apnea tips.6 min read
- Jet Lag Hawaii: Time Differences, Day-by-Day Plans and Why Flying Home Is HarderHawaii is 2 to 6 hours behind the mainland. Expect 2 to 4 days to adjust going there and 2 to 6 coming home. Plans for both legs and red-eyes.6 min read
- Jet Lag Japan to US: A Night-by-Night Plan for Tokyo to LA or New YorkFlying home from Tokyo takes about 7 to 10 days to adjust. Why LA is an 8-hour advance, why New York may shift the other way, and a day-by-day light plan.6 min read
- Jet Lag Europe to US: How to Recover After Flying Home From London or ParisFlying home from Europe takes about 4 days to adjust from London to New York and 6 from Paris to LA. Why you wake at 4 AM, and a night-by-night plan.5 min read
- Jet Lag From the US to Australia: A Day-by-Day Plan for LA or New York to SydneySydney is 14 to 19 hours ahead of the US, but your body can treat it as a 5 to 10 hour westward shift. Flight sleep times and a night-by-night plan.5 min read
- Jet Lag From the US to Asia: How to Adjust to Tokyo and Other Big Time ShiftsTokyo is 13 to 17 hours ahead of the US. Here's why that often acts like a westward shift, how long it takes, and a plan for LA or New York.4 min read
- Jet Lag From the US to Europe: A Day-by-Day Plan for New York to London or ParisA concrete plan for New York to London or Paris: what to do 3 days before, on the flight, and each night after you land, with exact times.4 min read
- Why Is Jet Lag Worse Flying East? East vs. West, ExplainedFlying east is harder because your body clock resists running early. Here's why, plus how many days each direction usually takes to recover.4 min read
Free sleep tools
Every tool is completely free, no sign-up.
- Sleep CalculatorBest bedtime or wake-up time, based on 90-minute sleep cycles.
- Hours of Sleep CalculatorHow many hours of sleep you will get between bedtime and your alarm.
- Nap CalculatorWhen to set your alarm for a power nap or a full-cycle nap.
- Sleep Debt CalculatorHow much sleep you owe this week, and how to pay it back.
- Caffeine Cutoff CalculatorHow much caffeine is still in you at bedtime, and your latest cup.
- Sleep Needs by AgeRecommended hours for every age, from newborns to over-65s.
- Sleep Efficiency CalculatorWhat share of your time in bed you actually spend asleep.
- Shift Work Sleep CalculatorWhen to sleep and stop caffeine around any shift, including nights.
- Kids Bedtime CalculatorThe right bedtime for your child's exact age and wake-up time.
- Chronotype CalculatorNight owl or early bird? Find your chronotype and social jet lag.
- Daylight Saving Time Sleep PlannerA day-by-day plan to shift your sleep before the clocks change.
- Sleep Schedule MakerA full daily timeline from your wake-up time: light, coffee, dinner, wind-down.
- Caffeine Limit CalculatorHow much caffeine you can have today, and how much is left.
- Sleep Deprivation QuizTen quick questions to see if you are running short on sleep.
- Jet Lag CalculatorDays to adjust, plus a shift-before-you-fly schedule.