Sleep Calculator

Calculate optimal sleep schedules and wake times.

How to Do It Manually

Sleep cycles last about 90 minutes. Waking between cycles feels refreshed; waking mid-cycle feels groggy. Add 14 minutes for falling asleep.

Total Sleep Time = (number of cycles × 90 min) + 14 min
  1. Choose how many complete 90-minute sleep cycles you want (4–6 is typical).
  2. Multiply by 90 minutes.
  3. Add 14 minutes for falling asleep.
  4. Count back from your wake time to find your ideal bedtime.

Frequently Asked Questions

Are sleep cycles always 90 minutes?

Approximately. Cycles vary from 80–100 minutes depending on individual sleep patterns.

Is 5 or 6 cycles better?

Most adults feel refreshed after 5–6 cycles (7.5–9 hours). Experiment to find your optimal number.