Nap calculator & power nap timer
How long should you nap?
The best naps are short — 10 to 20 minutes — or a full 90-minute cycle. Anything in between risks waking you from deep sleep, groggy. Pick a length and we'll set your wake-up time.
- Power nap
- A 10–20 minute nap that stays in light sleep, boosting alertness without grogginess.
- Sleep inertia
- The heavy, foggy grogginess you feel when woken from deep sleep — the reason 30–60 minute naps can backfire.
- Full-cycle nap
- A ~90 minute nap that completes one sleep cycle, so you wake from light sleep again — refreshing, good for memory and creativity.
Which nap length is right?
Naps work best at the two ends. Stay short to skip deep sleep, or go long enough to clear it.
Power nap10–20 min
The sweet spot for most people. Quick lift in alertness and mood, and you wake before deep sleep, so no grogginess.
Short nap30 min
Borderline. You may start slipping into deep sleep, so expect a few minutes of grogginess on waking.
Slow-wave nap60 min
Helps memory, but you'll likely wake mid deep sleep — the groggiest option. Use only if you can shake it off.
Full-cycle nap90 min
A complete cycle including REM. You wake from light sleep feeling clear — great for creativity and a big sleep debt.
Common questions
How long should a nap be?
For most people, 10–20 minutes (a power nap) for quick alertness, or a full 90-minute cycle. The 30–60 minute range risks waking from deep sleep and feeling groggy.
What is a power nap?
A short nap of about 10–20 minutes that keeps you in light sleep, boosting alertness and mood without the grogginess of deep-sleep waking.
Why do I feel worse after a nap?
A 30–60 minute nap often ends in deep (slow-wave) sleep, causing sleep inertia — heavy grogginess that can last 15–30 minutes. Keep it under 20 minutes or extend to 90.
When is the best time to nap?
Early afternoon, generally before 3 PM. Later or longer naps reduce your sleep pressure at night, making it harder to fall asleep at bedtime.
References & method · 参考来源与方法
Nap guidance uses the widely cited ~90-minute sleep cycle and the light-sleep window of the first ~20 minutes. This tool is for general use and is not medically reviewed; for ongoing sleep problems, consult a qualified professional.
- National Sleep Foundation (NSF) — napping guidance
- American Academy of Sleep Medicine (AASM)
- Centers for Disease Control and Prevention (CDC) — sleep
- Mednick S. et al. (2003), Nature Neuroscience — nap and performance
For night sleep, not just naps
Naps are a patch. For the real fix, time your bedtime to land at the end of a sleep cycle — or wind down first with a breathing session.
Sleep calculator → Breathing timer →