What is a sleep cycle?

A typical sleep cycle lasts ~90 minutes and includes light, deep and REM sleep. Waking at the end of a cycle usually feels more refreshed.

How many sleep cycles should I aim for?

Most adults benefit from 4–6 full sleep cycles (about 6–9 hours). Individual needs vary.

Can this tool replace medical advice?

No — this tool provides general guidance. For sleep disorders or persistent problems, consult a healthcare professional or sleep specialist.

Sleep Cycle Calculator

Calculate ideal bedtimes or wake times based on 90-minute sleep cycles. Enter either the time you need to wake up (we'll give bedtimes) or the time you plan to sleep (we'll give wake times).

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Time

Average time to fall asleep (minutes)

Note: Sleep cycles are approximate (≈90 minutes). Aim for 4–6 full cycles (6–9 hours) for most adults. Adjust fall-asleep time based on your experience.

Sleep Cycle — Guidance & FAQ

Using cycle-based timings can help alignment with natural sleep architecture, but quality, timing and duration all matter for restorative sleep.

FAQ

What if I wake up during a cycle?

If you wake during deep sleep you may feel groggy; try to return to sleep and aim for next cycle end where possible.

How accurate are 90-minute cycles?

90 minutes is an average; individual cycles vary (70–110 minutes). Use this as a practical heuristic, not a precise measure.