Sleep Cycle Calculator
Find the best time to wake up based on 90-minute sleep cycles. Free bedtime and wake-up calculator.
Frequently asked questions
- How does the 90-minute sleep cycle work?
- Sleep runs in cycles of roughly 90 minutes. The tool counts back from your wake time in whole cycles and suggests bedtimes for six, five, four and three cycles.
- What is the fall-asleep setting for?
- It subtracts the minutes you typically need to drift off, so the suggested bedtimes account for that delay instead of assuming you fall asleep instantly.
- Why wake up between cycles?
- Waking in the middle of a cycle tends to leave you groggy, while waking at the end of one usually feels easier even after less total sleep.
- How much sleep do I actually need?
- Most adults function best on seven to nine hours, which is five to six full cycles on this calculator.
This tool runs entirely in your browser. No data is uploaded anywhere.