Nap Calculator
A good nap refreshes; a bad one leaves you worse. The Restcalc Nap Calculator takes your current time and shows the best window — either a short power nap or a full 90-minute cycle — so you wake alert instead of groggy.
Two nap lengths that actually work
A 10–20 minute power nap stays in light sleep, so you wake alert with no grogginess. A full 90-minute nap completes a cycle, including some REM, and also leaves you refreshed.
Both avoid the danger zone in between — the part that backfires.
Why 30–60 minutes is the trap
A nap of about 30–60 minutes often drops you into deep sleep. Waking from there causes sleep inertia — that heavy, disoriented feeling. That is why a "quick 45-minute nap" can leave you worse than no nap.
If you only have an hour, a 20-minute nap is usually the safer bet. The Nap Calculator picks the length that fits your clock.
Timing matters as much as length
Nap early in the afternoon. A late nap steals sleep pressure from the coming night and makes bedtime harder. The calculator factors your current time so the suggestion fits the day you are in.
As a rule of thumb, finish napping by early-to-mid afternoon.
Who benefits most
Naps help shift workers, people carrying a sleep debt, or anyone with a post-lunch dip. They are a top-up, not a substitute for a full night of sleep.
Tips for a clean nap
- Set an alarm so you don't drift into deep sleep.
- Keep the room dark and cool.
- Avoid caffeine right before a nap.
- If naps hurt your nighttime sleep, move them earlier or drop them.
Related tools
Napping is one lever. These Restcalc tools plan the rest:
- Nap Calculator — best window for your current time.
- Caffeine Cutoff Calculator — keep caffeine from blocking sleep.
- Sleep Duration Calculator — see last night's cycles.
- Bedtime Calculator — plan tonight's bedtime.
Sources
- National Sleep Foundation — napping guidance.
- Sleep Foundation — Napping — power nap vs full-cycle nap.
- Centers for Disease Control and Prevention — Sleep — sleep hygiene.