Nap Calculator

How long should you nap?

The best nap length depends on your goal. A short power nap of about 20 minutes keeps you in light sleep, so you wake up alert without the fog. A full 90-minute cycle takes you through deep sleep and REM and lets you wake at the end of a cycle, which is better for memory and recovery when you have the time.

The window to avoid is roughly 30 to 60 minutes. An alarm there often pulls you out of deep sleep and leaves you groggy, a feeling called sleep inertia. This calculator shows both good options and flags the groggy window so you can set your alarm with confidence.

Keep naps to the early or mid afternoon. Napping too late can make it harder to fall asleep at night. If that is a struggle for you, our sleep habits guide and bedroom setup guide can help.

Frequently Asked Questions

How long should a nap be?

For a quick alertness boost, keep it to about 10 to 20 minutes so you stay in light sleep. For deeper recovery, a full 90-minute cycle lets you wake at the end of a cycle. Naps of roughly 30 to 60 minutes are the ones most likely to leave you groggy.

Why do I feel groggy after a nap?

That heavy, foggy feeling is called sleep inertia. It happens when your alarm pulls you out of deep sleep partway through a cycle. Keeping naps short, around 20 minutes, or long enough for a full 90-minute cycle usually avoids it.

When is the best time to nap?

Early to mid afternoon, roughly between 1pm and 3pm, works best for most people. Napping too late in the day can make it harder to fall asleep at night.

Are naps good or bad for you?

Short naps can boost alertness and mood for most people. Long or late naps can interfere with nighttime sleep, so they are not ideal for everyone, especially if you already struggle to fall asleep at night.