Health

Sleep Cycle Calculator — Free, No Upload, Browser-Based

🔒 Funciona en tu navegador

Enter your bedtime and instantly see the best times to wake up across 3–6 complete 90-minute sleep cycles — or work backwards from your alarm to find the ideal time to fall asleep. All calculations happen locally in your browser; no data is sent to any server. Wake up feeling rested, not groggy.

Cómo usar esta herramienta

  1. Choose your mode: calculate wake-up times from a bedtime, or find the right bedtime given a fixed alarm.
  2. Enter your bedtime or wake-up time using the time picker.
  3. Read off the optimal times — aim for a 5- or 6-cycle slot (marked Ideal) for 7.5–9 hours of sleep.
Calculate

Optimal wake-up times

3 cycles · 4h 30m
03:15
4 cycles · 6h
04:45
5 cycles · 7h 30mIdeal
06:15
6 cycles · 9hIdeal
07:45

Includes a 15-minute sleep onset buffer. Waking at the end of a cycle (5–6 cycles, 7.5–9 h) leaves you feeling most rested.

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Sleep Cycle Calculator — Free, No Upload, Browser-Based | brevio