Nap planning
Estimate a short nap, a longer rest window, or the latest wake-up time before a deadline. The result is a planning aid, not a promise about sleep stages or alertness.
Quick answer
A short nap of about 20 minutes may be easier to wake from for many people, while a longer 90-minute window gives more time for rest. Add a few minutes to fall asleep, avoid napping too close to bedtime when possible, and treat the result as a scheduling estimate, not medical advice.
Nap planner
Suggested wake time
A short nap may be easier to wake from for some people.
Educational estimate only. It does not evaluate sleep disorders, medications, health conditions, shift work, or personal safety needs.
Use the short option when you want a smaller rest break and the longer option when you have enough time to wake more gradually. Sleep timing varies by person, prior sleep, caffeine, stress, light exposure, and health factors.
If you already know your usual bedtime, enter it to flag naps that may be close enough to bedtime to affect nighttime sleep for some people.
This calculator does not decide whether you are safe to drive, work, supervise someone, or operate machinery. If you feel dangerously sleepy, stop the risky activity.
For recurring insomnia, excessive daytime sleepiness, loud snoring, breathing pauses, or concerns about a child's sleep, consider advice from a qualified healthcare professional.
A short nap may be easier to wake from for many people, but the best length depends on your schedule, prior sleep, and how you respond to naps.
A nap may help with temporary sleepiness, but it is not a full replacement for regular nighttime sleep. General adult guidance still emphasizes enough sleep across the full 24-hour period.
The wake time should include your estimated time to fall asleep. SleepPrism uses five minutes by default for this tool, and you can adjust it.
SleepPrism uses cautious educational language for sleep planning. Material health statements still require independent clinical review before being described as clinically reviewed.
NHLBI stages of sleep · CDC sleep basics · Review our sources