😴 Sleep Calculator

Sleep cycles last about 90 minutes per cycle. Waking during light sleep leaves you more refreshed, so recommended bed and wake times are counted back by 'cycles × 90 minutes'. Most adults need 4–6 full cycles (6–9 hours).

Note: results include a ~15-minute 'wind-down buffer' after falling asleep (from getting into bed to actually sleeping). It's best to go to bed that much earlier.