Sleep Calculator
Calculate the optimal bedtime or wake-up time based on sleep cycles to wake up feeling refreshed.
Published by:
isCalculator Editorial Team
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How to use this tool?
This calculator helps you find the best time to wake up or go to bed based on 90-minute sleep cycles.
- Choose calculation mode: Select "Wake-up time" to find when to wake up, or "Bedtime" to find when to go to bed.
- Enter your time:
- If calculating wake-up time: enter your planned bedtime.
- If calculating bedtime: enter your required wake-up time.
- Adjust fall asleep time: Enter the average minutes it takes you to fall asleep (default is 15 minutes, range 0–120).
- Click "Calculate": The result shows 3–5 sleep cycle options with their corresponding times.
How it works: Each sleep cycle lasts 90 minutes. The calculator adds or subtracts cycles from your input time, accounting for the time to fall asleep. Aim for 3–5 cycles for optimal rest.
Note: Times use 12-hour format with AM/PM. All inputs are in hours:minutes and minutes (no metric/imperial concerns).
Previous Results
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Frequently Asked Questions
It calculates optimal times based on 90-minute sleep cycles. You input your bedtime or wake-up time, and it suggests times that align with completing full cycles.
Research suggests that sleep cycles last about 90 minutes on average. Waking up at the end of a cycle leaves you feeling more refreshed.
You can adjust the 'minutes to fall asleep' field. The calculator accounts for that time in the calculation.
