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Sleep Calculator
Calculate optimal sleep and wake times based on sleep cycles
sleepsleep cyclebedtime
📖 How to Use
- Choose mode (by wake-up time or bedtime)
- Enter the target time
- Click Calculate to see recommended sleep/wake times
📐 Formula
Each sleep cycle ≈ 90 minutes Recommended: 5–6 cycles (7.5–9 hours) Falling asleep takes about 15 minutes
❓ FAQ
How many cycles are best?▾
5 cycles (7.5 hours) suits most adults; 6 cycles (9 hours) is better if you need more rest.
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About Sleep Calculator
This tool is completely free, no registration required. Works directly in your browser. Supports both PC and mobile devices.
Sleep Calculator is a free online tool that works on both PC and mobile. No registration or download required — just open in your browser. Results are accurate and reliable for everyday use and professional reference.