Sleep Cycle Planning Calculator
Plan bedtimes or wake-up times around roughly 90-minute sleep cycles, allowing for time to fall asleep.
Your inputs
Results
Suggested bedtime (5 cycles)
23:15
- 6 cycles
- 21:45
- 4 cycles
- 00:45
≈Estimate based on the stated model and assumptions
Notes for this result
- Sleep cycles average about 90 minutes but vary between people and through the night, so treat these times as rough guides.
| Cycles | Sleep (h) | Go to bed at |
|---|---|---|
| 6 | 9 | 21:45 |
| 5 | 7.5 | 23:15 |
| 4 | 6 | 00:45 |
Inputs are never added to links for financial, salary or health calculators.
What this calculator does
Some people wake more refreshed at the end of a sleep cycle. This planner suggests times that fit whole cycles.
Formula and method
Worked example
Calculated by this tool with its default inputs:
Inputs
- I want to: Wake up at a set time
- Time: 07:00
- Minutes to fall asleep: 15
- Cycle length: 90 minutes
Results
- Suggested bedtime (5 cycles): 23:15
- 6 cycles: 21:45
- 4 cycles: 00:45
How to read the results
Five or six cycles (7.5–9 hours) fit the adult recommendation.
Assumptions and limitations
- Cycle length varies between people and across the night; treat the times as approximate.
Health results are general estimates for adults and do not replace medical advice, diagnosis or treatment. Speak to a qualified health professional about your personal situation, especially during pregnancy or if you have a medical condition.
Questions
Are sleep cycles always 90 minutes?
They average around 90 minutes but commonly range from about 70 to 120.
Methodology and verification
- Result type
- Estimate based on the stated model and assumptions
- Formula version
- 1.0
- Automated verification
- 3 reference and validation test cases, checked against independently computed values. The site cannot be built if any of them fail.
- Editorial review
- Awaiting human editorial review. The explanation was drafted with AI assistance; the formula and examples are verified by the automated tests above.
Privacy
Everything you enter is calculated in this browser and is not sent to Numerith or anyone else. Because this calculator can involve personal financial or health details, your inputs are never added to share links or saved to history. Privacy policy