Nap Calculator
Napping now? This shows the best alarm time for each common nap length, starting from the current time plus about 15 minutes to fall asleep. A 10–20 min power nap or a full 90 min cycle works best — avoid the groggy 30–60 min window.
Best nap lengths
| Nap length | Best for | Wake-up feel |
|---|---|---|
| 10–20 min | Quick alertness, focus | Refreshed, no grogginess |
| 30 min | Generally avoid | Some grogginess |
| 60 min | Remembering facts & places | Possible deep-sleep grogginess |
| 90 min | Full cycle, creativity, REM | Refreshed |
Why 20 or 90 minutes?
In the first 20 minutes of sleep you stay in light stages, so waking is easy and you get an alertness boost without sleep inertia. If you sleep 30–60 minutes you slide into deep (slow-wave) sleep, and being woken from it leaves you groggier than before the nap. By 90 minutes you've completed a whole cycle and come back up to light sleep and REM, so waking feels natural again.
Tips for a better nap
- Nap early — before about 3 PM — so it doesn't disrupt your night.
- Keep it short (20 min) on workdays; save 90-minute naps for days off.
- A "coffee nap" — caffeine right before a 20-minute nap — can amplify alertness.
- Dark, cool, quiet room and an alarm so you don't oversleep.
General guidance only, not medical advice. If you feel a constant need to nap, talk to a doctor.
Related
Full sleep calculator · If I go to sleep now · How much sleep by age · What is a sleep cycle?