Why nap length matters
A 10–20 minute nap is often used as a quick reset. A longer nap may include deeper sleep and REM sleep, but it can also leave some people groggy when the alarm interrupts a deeper stage.
There is no universal perfect nap length. The right choice depends on how much time you have, how you usually feel after napping and whether a nap will make it harder to sleep at night.
What the calculator assumes
- You choose a 20, 30, 60 or 90-minute nap.
- The default sleep latency is 10 minutes and can be adjusted.
- Times use your device's local clock.
- The result is a planning estimate, not a measurement of your sleep stages.
Late or long naps are not right for everyone. If you struggle with insomnia, a long nap late in the day may make nighttime sleep harder. Persistent sleepiness is worth discussing with a qualified professional.
Related reading
Read the practical nap guide for timing, sleep inertia and environment tips, or return to the one-night sleep calculator.