What is this calculator?
Estimate bedtimes using a chosen sleep duration and time to fall asleep.
What can you use it for?
Use it for practical planning, conversions, measurement or checking the result described here. Estimate bedtimes using a chosen sleep duration and time to fall asleep.
How to use it
- Enter wake-up time.
- Enter chosen sleep duration (hours).
- Enter minutes to fall asleep.
- Select Calculate (or Generate for random tools).
- Read the answer and any additional results below the form. Check the units and the limits of the method.
Formula and method
The clock calculation wraps to the previous day when needed.
Worked example
Wake-up time: 07:00, Chosen sleep duration (hours): 8, Minutes to fall asleep: 15. The result is 22:45 (planned bedtime).
Assumptions and limits
Time planning only. Sleep needs vary; this does not predict exact sleep cycles.
Frequently asked questions
What inputs does the Sleep Calculator need?
Use wake-up time, chosen sleep duration (hours), minutes to fall asleep. Read the answer and any additional results below the form. Check the units and the limits of the method.
What assumptions apply to the Sleep Calculator?
Time planning only. Sleep needs vary; this does not predict exact sleep cycles.