Overview
This tool calculates the time between bedtime and waking, including crossing midnight, and can add a nap. Duration alone does not reflect sleep quality or adequacy.
Formula
Both times are converted to minutes. If wake time is earlier than bedtime, add 1,440 minutes, then add nap minutes.
How it works
Enter bedtime
The time you actually try to sleep.
Enter wake time
Waking the next day is handled automatically.
Add a nap
Optional, if you want total sleep.
Worked examples
23:00 to 07:00
Duration is 8 hours.
Same sleep with a 30-minute nap
Total is 8 hours 30 minutes.
Frequently asked questions
What if I wake after midnight?
The tool handles it automatically; just enter the two times.
Is 8 hours enough?
It may suit many adults, but needs are individual and depend on age and health.
Is time in bed the same as sleep?
Not necessarily. Time in bed can exceed actual sleep because of insomnia or restlessness.
Are 90-minute cycles exact?
It is a rough average. Cycles vary and change through the night, and are not used to diagnose sleep problems.
This calculator is for educational and informational purposes only and is not a substitute for professional advice.