Sleep Calculator
Calculate sleep schedules based on sleep cycles.
Includes ~15 minutes to fall asleep
Suggested bedtimes
11:15 PM
Based on 90-minute sleep cycles
6 cycles (~9.25 h)
9:45 PM
5 cycles (~7.75 h)
11:15 PM
4 cycles (~6.25 h)
12:45 AM
Sleep needs vary. These times aim to wake you near the end of a cycle — not a clinical sleep plan.
In-depth explanation
Plan bedtimes or wake times around 90-minute sleep cycles, including about 15 minutes to fall asleep. Everything runs locally in your browser — your inputs are not uploaded to produce the result.
Sleep typically moves through stages in roughly 90-minute cycles. Waking near the end of a cycle can feel easier. Most people need a short buffer to fall asleep before the first cycle starts.
Five or six cycles (about 7.5–9 hours including fall-asleep time) suits many adults. Use Sleep Calculator for quick planning; confirm important money, tax, or health decisions with an official source or professional when needed.
Frequently asked questions
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