Nap calculator
The length of a nap decides whether you wake sharp or groggy. Pick a nap type and we'll time the alarm.
Set your alarm for
1:50 PM
Power nap: 15 minutes of sleep after 5 minutes dozing off.
Good timing: early-afternoon dip, and 9 h 10 min before bed.
Nap length at a glance
| Length | What you get | Downside |
|---|---|---|
| 10–20 min | Quick alertness boost, better mood | Little, if any, grogginess |
| 30–60 min | Some deep sleep, memory benefits | Most likely to wake groggy |
| 90 min | A full cycle, incl. REM | Can reduce night-time sleepiness |
Naps are a patch, not a substitute. If you need one every day to get through, check your total with the sleep debt calculator. Night workers should use the shift work planner, which places a pre-shift nap for you.
Questions people ask
How long should a nap be?
For a quick boost, 10 to 20 minutes. That keeps you in light sleep, so you wake without grogginess. A full 90-minute nap includes a complete cycle and suits recovering from a very short night or before a night shift. Naps of 30 to 60 minutes are the most likely to leave you groggy.
What is a power nap?
A power nap is a short nap of roughly 10 to 20 minutes. A 2006 study by Brooks and Lack found a 10-minute nap gave the best overall balance of improved alertness and minimal grogginess.
What is a coffee nap?
Drinking a cup of coffee right before a 15 to 20-minute nap. Caffeine takes about 20 minutes to kick in, so it arrives as you wake. It is useful for drivers and shift workers, but avoid it late in the day.
What is the best time of day to nap?
Early afternoon, roughly 1 to 3 PM, when there is a natural dip in alertness. Napping later than about 3 PM (or within 6 to 7 hours of bedtime) can make it harder to fall asleep at night.
Why do I feel worse after a nap?
That is sleep inertia: you woke from deep sleep. Keep naps under 20 minutes, or go the full 90, and give yourself 10 to 15 minutes and some light after waking.
Sources
- Brooks A, Lack L (2006). A brief afternoon nap following nocturnal sleep restriction: which nap duration is most recuperative? Sleep, 29(6).
- Reyner LA, Horne JA (1997). Suppression of sleepiness in drivers: combination of caffeine with a short nap. Psychophysiology, 34(6).
- Tassi P, Muzet A (2000). Sleep inertia. Sleep Medicine Reviews, 4(4).