Sleep Cycle Calculator
Fill in the value and the answer updates as you type.
How the Sleep Cycle Calculator works
A sleep cycle lasts about 90 minutes, and most people need 5 to 6 of them. The times include roughly 15 minutes to fall asleep. Waking at the end of a cycle often feels easier than waking in the middle of one.
Inputs and results
The Sleep Cycle Calculator takes 1 input and gives 3 results.
What you enter
- Wake-up time — starts at 07:00.
What you get
- Bedtime for 6 cycles (9 hours)
- Bedtime for 5 cycles (7.5 hours)
- Bedtime for 4 cycles (6 hours)
Example: Sleep Cycle Calculator with the starting values
With wake-up time 07:00, the calculator returns:
| Bedtime for 6 cycles (9 hours) | 21:45 |
|---|---|
| Bedtime for 5 cycles (7.5 hours) | 23:15 |
| Bedtime for 4 cycles (6 hours) | 00:45 |
Change any value above and the results update straight away.
Sleep Cycle Calculator FAQ
How do I use the Sleep Cycle Calculator?
Enter wake-up time in the fields, then read bedtime for 6 cycles (9 hours), bedtime for 5 cycles (7.5 hours) and bedtime for 4 cycles (6 hours) in the result panel. The answer updates as you type, and you can press Calculate or Enter to refresh it. Use “Copy link” to share your exact numbers with someone else.
What does the Sleep Cycle Calculator calculate?
Bedtimes that match 90-minute sleep cycles for your wake-up time. It returns bedtime for 6 cycles (9 hours), bedtime for 5 cycles (7.5 hours) and bedtime for 4 cycles (6 hours) from the 1 value you provide.
What values does the Sleep Cycle Calculator start with?
It opens with wake-up time 07:00 so you can see a working result straight away. Replace them with your own numbers, or press Reset to return to these starting values.
Is the Sleep Cycle Calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so nothing you type is sent to or stored on our servers. See the Privacy Policy for details.
Can I rely on the Sleep Cycle Calculator for medical or health decisions?
Treat the result as a well-rounded estimate. Real situations often have details a general calculator cannot know, so confirm medical or health decisions with a qualified professional. See the Disclaimer for more.