Sleep Calculator

Calculate the best bedtime or wake-up time.

Sleep Cycle Calculator

Based on 90-minute sleep cycles

Time to fall asleep

Select a time to see recommended sleep/wake options.

Step-by-step Solution

Sleep Science

Sleep occurs in 90-minute cycles. Each cycle includes light sleep, deep sleep (NREM), and REM sleep.

Waking up between cycles helps you feel more rested than waking mid-cycle.

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About This Calculator

Calculate the best bedtime or wake-up time.

Everything is worked out in your browser as you type, so your figures never leave your device.

Pro Tips

Results update as you type — change any field to see the effect immediately.

Check that every value uses the same unit before comparing results.

Use the copy button to paste the sleep figures into a note or spreadsheet.

Nothing is sent to a server, so you can use this with private figures.