The caffeine in a drink matters less than when you drink it. A strong coffee at 8 AM is long gone by bedtime; a can of cola at 9 PM may not be. Here's how common drinks compare, and the latest time to have each one.
Free toolCaffeine Cutoff CalculatorHow much caffeine is still in you at bedtime, and your latest cup.How much caffeine is in common drinks?
An 8 oz brewed coffee has about 80 to 100 mg of caffeine, an espresso shot about 63 mg, an 8 oz black tea 30 to 50 mg and a 12 oz cola 30 to 40 mg.
| Drink | Typical caffeine |
|---|---|
| Brewed coffee, 8 oz | 80–100 mg |
| Espresso, 1 shot | about 63 mg |
| Black tea, 8 oz | 30–50 mg |
| Green tea, 8 oz | 30–50 mg (often toward the low end) |
| Cola, 12 oz can | 30–40 mg |
| Energy drink, per 8 oz | 40–250 mg |
| Decaf coffee, 8 oz | 2–15 mg |
These are typical amounts. Real numbers vary with brand, cup size and brewing method, and coffee-shop sizes are often 12 to 20 oz. Check the label when you can.
When should I stop caffeine for a 10:30 PM bedtime?
For a 10:30 PM bedtime, finish a regular 8 oz coffee by about 12:50 PM, an espresso by 3:45 PM and black tea by 5:55 PM.
This table uses an average caffeine half-life of 5 hours and shows when each drink would drop below about 25 mg by bedtime. That's not an official limit, but it's a sensible target.
| Drink | Caffeine | Latest time |
|---|---|---|
| Green tea, 8 oz | about 28 mg | 9:40 PM |
| Cola, 12 oz | about 34 mg | 8:15 PM |
| Black tea, 8 oz | about 47 mg | 5:55 PM |
| Espresso, 1 shot | about 63 mg | 3:45 PM |
| Energy drink, 8.4 oz | about 80 mg | 2:05 PM |
| Brewed coffee, 8 oz | about 95 mg | 12:50 PM |
| Energy drink, 16 oz | about 160 mg | 9:05 AM |
| Large coffee, 16 oz | about 190 mg | 7:50 AM |
| Pre-workout, 1 scoop | about 200 mg | 7:30 AM |
Different bedtime, different drink, or two coffees instead of one? The caffeine calculator works it out for your exact numbers and your own sensitivity.
Coffee cutoff for other bedtimes
For a single 8 oz brewed coffee (about 95 mg) and average sensitivity:
| Bedtime | Latest coffee |
|---|---|
| 9:00 PM | 11:20 AM |
| 10:00 PM | 12:20 PM |
| 11:00 PM | 1:20 PM |
| Midnight | 2:20 PM |
Two cups at once roughly doubles the dose, which pushes each cutoff about 5 hours earlier. Energy drinks deserve their own look: see energy drinks and sleep.
Why does caffeine last so long?
Caffeine blocks adenosine, the chemical that builds up while you're awake and makes you feel sleepy. The body clears caffeine slowly: in a typical adult, about half is gone after 5 hours, and a quarter is still there after 10.
That average hides big differences. For an hour-by-hour look at what happens to one cup, read how long caffeine lasts. Genetics, smoking, pregnancy, liver health and some medications can make caffeine last much longer, or clear faster. If you're sensitive, treat the table's times as too late.
Does caffeine affect sleep if you still fall asleep fine?
Yes, it can. Plenty of people say coffee doesn't affect them because they fall asleep easily. But in an at-home sleep study, a 400 mg dose taken 6 hours before bed still cut total sleep by more than an hour, and people generally didn't notice. Caffeine tends to make sleep lighter and shorter, not just harder to start.
How much is too much?
The FDA says up to 400 mg a day is generally not associated with negative effects for healthy adults. That's roughly four 8 oz cups of brewed coffee. But for sleep, timing matters as much as the total.
Easy ways to cut back without quitting
- Move your last cup earlier by 30 to 60 minutes a week.
- Switch the afternoon drink to half-caf, green tea or decaf. Decaf isn't quite zero; see decaf coffee before bed.
- Check energy drinks and pre-workouts. A single serving can carry two coffees' worth.
- Watch hidden caffeine in iced tea, some sodas and dark chocolate.