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Nap Calculator
Time your nap to wake up sharp — not groggy
The Two Naps That Actually Work
Not all naps are equal. Sleep science recognizes exactly two nap lengths that leave you better than before:
- 20 minutes — the power nap. Boosts alertness, mood, and performance for hours. Short enough that you never sink into deep sleep, so there’s no grogginess.
- 90 minutes — the full cycle. One complete sleep cycle including REM. Genuinely restorative — the closest thing to a night’s sleep in miniature.
Everything between 30 and 60 minutes is the danger zone: long enough to enter deep sleep, too short to finish the cycle. You wake mid-cycle with sleep inertia — that heavy, disoriented feeling worse than not napping at all.
When to Nap
The sweet spot is 1–3 PM, matching your natural post-lunch dip in alertness. Napping after 4 PM steals from tonight’s sleep. Keep the room dim, set a real alarm (don’t trust “just 20 minutes”), and give yourself 5 minutes to drift off — the calculator above builds that in.
Frequently Asked Questions
How long should a power nap be?
20 minutes. Research consistently shows 10–20 minutes maximizes alertness gains while avoiding sleep inertia.
Is a 2-hour nap too long?
Usually yes — 2 hours lands you mid-cycle in most cases. Either cap it at 90 minutes (one cycle) or take the full cycle plus buffer.
Why do I feel worse after napping?
You woke from deep sleep mid-cycle. Shorten to 20 minutes or extend to 90 — the in-between lengths cause the grogginess.
Can naps replace nighttime sleep?
No. Naps supplement but can’t replicate the full architecture of a night’s sleep — the deep-sleep and REM distribution is different.
Is napping a sign of poor nighttime sleep?
Needing a daily long nap often signals insufficient or low-quality night sleep. Occasional strategic naps are healthy; dependence is a symptom.
Disclaimer: General wellness information only, not medical advice.