Bedtime Calculator
Calculate a bedtime from desired wake time, sleep duration and optional sleep-onset buffer.
Enter or adjust the values above, then calculate.
Bedtime: when to Sleep for Your Wake Time
Calculate a bedtime from desired wake time, sleep duration and optional sleep-onset buffer.
Inputs this tool uses
- Wake time
- Desired sleep
- Sleep-onset buffer
What you get
Calculated bedtime from desired wake time, sleep duration and onset buffer.
How to use the Bedtime Calculator
- Enter wake time, desired sleep, sleep-onset buffer.
- 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 22:45. 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.
Questions people ask about Bedtime Calculator
Does the bedtime include time to fall asleep?
Yes, if you enter a sleep-onset buffer. The calculator subtracts both your desired sleep duration and the buffer from your wake time.
Connected tools
Continue with the closest related calculation without re-entering sensitive values automatically.
Plan a sleep window from desired bedtime/wake time and duration, with optional approximate cycle visualization.
Open tool →☾Wake-Up Time CalculatorCalculate a wake-up time from bedtime, desired sleep duration and optional sleep-onset buffer.
Open tool →☾Sleep Cycle CalculatorShow approximate cycle-aligned candidate bed/wake times without implying that every sleep cycle lasts exactly 90 minutes.
Open tool →