Sleep Duration Calculator
Calculate sleep duration between start and wake times, including overnight rollover.
Enter or adjust the values above, then calculate.
Sleep Duration: hours Between Sleep & Wake Time
Calculate sleep duration between start and wake times, including overnight rollover.
Inputs this tool uses
- Sleep start
- Wake time
What you get
Time between entered sleep start and wake time.
How to use the Sleep Duration Calculator
- Enter sleep start, wake time.
- Select any method, activity level or option shown on this page, then choose Calculate.
- Read the main result together with the supporting values, method, assumptions and limitations below before using the estimate.
How this calculation works
Sleep tools use date/time arithmetic. Any cycle-aligned suggestions are approximate and do not assume every sleep cycle is exactly 90 minutes.
Example calculation
The sample values loaded into the calculator produce 8h 0m. This example exists to show how the output is structured; replace the sample values with your own inputs for your calculation.
Assumptions and limitations
- Sleep needs and sleep-cycle length vary between people and nights.
- Use results for planning, not diagnosis of a sleep disorder.
Sources and review status
Source set last verified 2026-09-25. No clinician review is claimed unless a real named reviewer is displayed.
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