Sleep Cycle Calculator
Accurate calculators with instant results.
What does this tool do?
Find the best bedtimes and wake times using 90-minute sleep cycles.
Key features
- Instant calculation
- Accurate formulas
- Clear result breakdown
- Mobile-friendly inputs
Sleep Cycle Calculator
Find the best bedtimes and wake times using 90-minute sleep cycles.
What does this tool do?
Find the best bedtimes and wake times using 90-minute sleep cycles. This free online tool works instantly in your browser — no signup, no download, no watermark.
Key Features
- 90-minute sleep cycle science
- Bedtime from wake time
- Wake time from bedtime
- 15-minute wind-down buffer
Based on 90-minute sleep cycles plus about 15 minutes to fall asleep. Waking at the end of a cycle helps you feel more refreshed.
Frequently Asked Questions
What is a sleep cycle?
A sleep cycle lasts about 90 minutes and moves through light sleep, deep sleep and REM sleep. Waking at the end of a cycle usually feels better than waking mid-cycle.
Why add 15 minutes?
Most people need around 15 minutes to fall asleep, so the calculator adds this wind-down time to the cycle math.
How many cycles do I need?
Most adults feel best with 5 to 6 full cycles, which is 7.5 to 9 hours of sleep.
Is this medical advice?
No. It is a general guideline. See a doctor if you have ongoing sleep problems.
How to Use Sleep Cycle Calculator
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