Most people aren't strictly one or the other: chronotypes run on a spectrum, with a few strong early birds, a few strong night owls, and most of us somewhere in between. Your spot on that spectrum is partly genetic and changes with age, and you can shift it by an hour or two with light and a steady schedule, though you probably can't turn a true owl into a lark.
Free toolSleep CalculatorBest bedtime or wake-up time, based on 90-minute sleep cycles.What a chronotype is
Your chronotype is your body clock's natural timing: when you tend to get sleepy, when you'd wake without an alarm, and when you feel sharpest.
Researchers who surveyed tens of thousands of people found that preferred sleep times fall along a near bell-shaped curve. At the extremes, the earliest types are waking up around the time the latest types are falling asleep.
How to tell which one you are
The clearest clue is what you do when nothing forces your schedule, like on vacation or a string of free days.
| Sign | Leaning early bird | Leaning night owl |
|---|---|---|
| Free-day wake-up without an alarm | Early, even on weekends | Late morning or later |
| When you feel sharpest | Morning | Late afternoon or evening |
| Workday mornings | Fairly easy | A struggle, heavy on the snooze |
| Weekend sleep | Close to weekday times | Much later than weekdays |
| Evening energy | Fades after dinner | Picks up after 9 PM |
Online chronotype quizzes, including the kind you might see on this site, can be a fun way to reflect on your habits. They aren't a diagnosis, and they can't measure your actual body clock. A week of noting when you naturally get sleepy and wake up on free days tells you more.
Is it genetic?
Partly. A large genetic study of nearly 700,000 people found 351 gene regions linked to being a morning person. People carrying the most "morning" variants slept about 25 minutes earlier, on average, than those carrying the fewest.
That's a real effect, but a modest one. Genes nudge you in a direction. Light, schedule, age and habits do a lot of the rest.
It changes with age
Chronotype tends to shift later through the teenage years, reaching its latest around the early twenties, then gradually moves earlier through adulthood. That's why a college student and their grandparent can have genuinely different natural bedtimes, and why many people become earlier risers as they get older without trying.
Can a night owl become an early bird?
You can move your clock earlier, often by a meaningful amount, but it takes consistency.
In a small trial, night owls followed a few simple rules for several weeks: wake up and go to bed earlier, get morning daylight, eat meals at fixed times, and move caffeine and exercise earlier in the day. Their sleep and body clocks shifted about 2 hours earlier without losing sleep, and they reported less stress and depression and better morning performance.
A gradual shifting plan
If you currently sleep from 1:00 AM and want to get to 11:30 PM, move 15 minutes every 3 days. Each wake time below gives 5 full sleep cycles plus 15 minutes to fall asleep.
| Days | Bedtime | Wake-up |
|---|---|---|
| 1 to 3 | 1:00 AM | 8:45 AM |
| 4 to 6 | 12:45 AM | 8:30 AM |
| 7 to 9 | 12:30 AM | 8:15 AM |
| 10 to 12 | 12:15 AM | 8:00 AM |
| 13 to 15 | 12:00 AM | 7:45 AM |
| 16 to 18 | 11:45 PM | 7:30 AM |
| 19 onward | 11:30 PM | 7:15 AM |
What makes it work:
- Bright light right after waking. Outdoors is best, even on a cloudy day.
- Dim evenings. Low lamps and fewer screens in the last hour.
- Keep the new wake-up time on weekends. A big weekend lie-in drags your clock right back. More on that in is it bad to sleep in on weekends.
For more tactics, see how to go to bed earlier.
Working with your chronotype instead of against it
Sometimes the better move is to adapt your day rather than fight your clock.
- Night owls: protect your mornings from hard thinking where you can. Schedule demanding work for late morning or afternoon. Keep your alarm consistent so the gap between weekday and weekend sleep stays small.
- Early birds: do your most focused work early. Be careful with late social plans: you may still wake at dawn, so a late night costs you sleep.
- Everyone: pick a wake-up time you can hold 7 days a week, then use the sleep calculator to set a bedtime that gives you enough sleep. The how much sleep do I need tool shows the target for your age.
When it's more than a preference
If your natural sleep time is extremely late (say, you can't fall asleep before 3 or 4 AM no matter what you try) and it's hurting your work or health, talk to a doctor. The same goes for insomnia lasting weeks or heavy daytime sleepiness. A sleep specialist can help with timed light and other approaches.