Sleep calculator
Estimate bedtimes or wake-up times using approximate 90-minute sleep-cycle intervals.
About the estimate
Sleep is not a set of perfectly uniform 90-minute blocks. This tool uses cycle timing only as a planning approximation, not as medical advice.
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Sleep planning tools
Bedtime calculatorWork backward from a wake-up timeWake-up calculatorEstimate times after going to bedSleep-cycle calculatorSee cycle-based intervalsSleep by ageGeneral duration context
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How to use a sleep calculator
Choose when you want to wake or when you expect to go to bed. The tool adds or subtracts an estimated time to fall asleep and then shows several cycle-based options. Treat the results as schedule ideas, not a prescription for how much sleep you personally need.
Why the results are approximate
Sleep stages and cycle lengths vary among people and across the night. Stress, illness, age, medication, alcohol, light exposure and many other factors can affect sleep timing and quality.