Nap Calculator
Pick when your nap starts and get end times that let you wake up clear headed instead of groggy.
Earlier naps interfere less with nighttime sleep.
Your nap end times will appear here after you calculate.
How it works
Naps work best at two lengths. A short nap of 20 to 30 minutes stays in light sleep, so waking up feels easy. A 90 minute nap allows roughly one full cycle, which is also easy to wake from. The groggy zone sits in between, where an alarm can catch you in deep sleep.
Timing matters as much as length. Naps earlier in the afternoon interfere less with nighttime sleep than evening naps. If you find yourself napping late most days, it may be a sign that nighttime sleep needs attention first.
These calculators give planning estimates based on average sleep cycle timing. They are not medical advice and cannot diagnose sleep problems. If poor sleep persists, talk to a clinician.