DozeClock › Naps

How long should a nap be? 10 to 90 minutes, and when to take it

Short naps stay in light sleep and refresh quickly; anything past about 30 minutes risks waking from deep sleep groggy. NASA's pilots got a 34% performance lift from 26 minutes. Pick a length or a start time.

Updated October 3, 2026 · NASA 1995 · Brooks & Lack 2006 · Tassi & Muzet 2000

Nap length versus grogginess on waking
10 mingrogginess: minimal20 mingrogginess: low26 mingrogginess: low to moderate30 mingrogginess: moderate45 mingrogginess: moderate to high60 mingrogginess: high90 mingrogginess: low

Green: little or no sleep inertia · amber/red: likely grogginess · as of October 3, 2026

By length

10 minlight sleep (N1-N2) · grogginess minimal20 minlight sleep (N2) · grogginess low26 minlight sleep, occasionally early deep sleep · grogginess low to moderate30 minoften enters deep sleep (N3) · grogginess moderate45 mindeep sleep (N3) likely · grogginess moderate to high60 mindeep sleep (N3) · grogginess high90 mincomplete cycle including REM · grogginess low (waking near the end of a cycle)

By start time

Nap at12:00 pm20 min → up at 12:35 pmNap at12:30 pm20 min → up at 1:05 pmNap at1:00 pm20 min → up at 1:35 pmNap at1:30 pm20 min → up at 2:05 pmNap at2:00 pm20 min → up at 2:35 pmNap at2:30 pm20 min → up at 3:05 pmNap at3:00 pm20 min → up at 3:35 pmNap at3:30 pm20 min → up at 4:05 pmNap at4:00 pm20 min → up at 4:35 pmNap at4:30 pm20 min → up at 5:05 pmNap at5:00 pm20 min → up at 5:35 pm

Nap calculator

Pick any start time and length →

Sources

  1. A brief afternoon nap following nocturnal sleep restriction: which nap duration is most recuperative? — Sleep 29(6):831-840, 2006 (Brooks A., Lack L.)
  2. Alertness Management: Strategic Naps in Operational Settings — NASA Technical Memorandum 108839 (Rosekind M.R. et al.), 1995; also J Sleep Res 4(S2):62-66
  3. Sleep inertia — Sleep Medicine Reviews 4(4):341-353, 2000 (Tassi P., Muzet A.)
  4. Brain Basics: Understanding Sleep — NINDS (NIH)

General information from population studies (NIH, CDC, NSF, AASM). It is not medical advice and does not replace a clinician who knows you.