Nap calculator
A nap can leave you sharp or groggy depending entirely on its length. Tell the calculator when you’re lying down and it shows when to set your alarm for each kind of nap — so you wake during light sleep, not deep sleep.
Which nap length should I choose?
- 20 minutes — the power nap. Stays in light sleep, so you wake quickly with a clear alertness boost and no grogginess. The safest choice for most people, any time of day.
- 30 minutes — the danger zone. Just long enough to start slipping into deep sleep but not long enough to finish a cycle, so you often wake up groggy. Either shorten to 20 or extend to 90.
- 60 minutes — the memory nap. Reaches deep sleep, which is great for learning and recall — but expect some grogginess on waking. Good before an exam if you have time to shake it off.
- 90 minutes — the full-cycle nap. One complete cycle through light, deep, and REM sleep, returning to light sleep just as you wake. The most restorative option when you have the time.
Tips for a better nap
Nap in the early-to-mid afternoon (roughly 1–3 PM) to ride your natural post-lunch dip without stealing pressure from your nighttime sleep. Avoid napping after about 4 PM. For an instant boost, try the coffee nap: drink a coffee, then lie down for 20 minutes — the caffeine kicks in just as you wake.
Want the science? Read our complete power nap guide, or use the full sleep calculator for nighttime sleep.