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Sleep Cycle Calculator — Free Online (Tolyo.app)

Best sleep/wake times aligned to cycles.

Sleep Cycle Calculator
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Time you typically take to fall asleep.

Suggested bedtimes
Based on 90-min cycles • latency 14 min
  • Option 1
    Mon, Sep 22 • 09:45 PM
  • Option 2
    Mon, Sep 22 • 11:15 PM
  • Option 3
    Tue, Sep 23 • 12:45 AM
  • Option 4
    Tue, Sep 23 • 02:15 AM

Tip: Aim for 4–6 cycles (6–9 hours). If the result is before now, pick the next option or adjust the date.

How the Sleep Cycle Calculator Works

This Tolyo.app free online tool uses typical 90-minute sleep cycles. Waking at the end of a cycle usually feels easier than waking mid-cycle. We also include sleep latency (the time it takes you to fall asleep), which defaults to 14 minutes but can be customized.

Quick science (in plain language)

  • Sleep cycles alternate between non-REM and REM approximately every ~90 minutes.
  • Many people feel more refreshed when waking at the end of a cycle instead of the middle.
  • Average latency to fall asleep is around 10–20 minutes; adjust this to match your experience.
  • Consistent bed/wake times support your circadian rhythm; light exposure in the morning can help.

Example

If you must wake at 07:00 and your latency is 14 minutes, suggested bedtimes are roughly: 22:16 (6 cycles), 23:46 (5 cycles), 01:16 (4 cycles), or 02:46 (3 cycles).

These are guidelines; individual needs vary. For sleep disorders or persistent issues, consult a clinician.

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