Sleep Calculator
Pick a wake time or a bedtime and see options based on 90-minute sleep cycles, including time to fall asleep. Not medical advice — a simple schedule helper only.
Frequently asked questions
How long is a sleep cycle?
This tool uses 90-minute cycles. 7.5 hours (five cycles) often feels better than a round 8 hours, which can land mid-cycle.
Is this medical advice?
No. It is a simple schedule helper for planning bed and wake times — not a diagnosis, treatment, or medical advice.
Is my data sent to a server?
No. This calculator runs entirely in your browser. Nothing you type is uploaded.