Sleep Cycle Planner
Work out the best bedtimes or wake times around real ~90-minute sleep cycles, with sleep-onset latency and your age-based sleep need taken into account.
Most people need 10–20 minutes to fall asleep. That time is subtracted from your sleep total and pushed onto the start of the block.
Reference need for this band: 7–9 hours per night.
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Best bedtimes
| Time | Cycles | Time asleep | Efficiency | Quality | Sleep debt |
|---|---|---|---|---|---|
| 21:30 | 6 | 8h 45m | 97% | 90 · Excellent | on target |
| 21:20 | 6 | 8h 55m | 97% | 88 · Excellent | on target |
| 21:15 | 6 | 9h 00m | 97% | 87 · Excellent | on target |
| 21:10 | 6 | 9h 05m | 97% | 86 · Excellent | on target |
| 21:00 | 6 | 9h 15m | 97% | 85 · Excellent | on target |
| 22:30 | 5 | 7h 45m | 97% | 80 · Good | 0h 15m |
| 22:40 | 5 | 7h 35m | 97% | 78 · Good | 0h 25m |
| 22:45 | 5 | 7h 30m | 97% | 77 · Good | 0h 30m |
| 22:50 | 5 | 7h 25m | 97% | 76 · Good | 0h 35m |
| 23:00 | 5 | 7h 15m | 97% | 75 · Good | 0h 45m |
| 00:00 | 4 | 6h 15m | 96% | 48 · Fair | 1h 45m |
| 00:10 | 4 | 6h 05m | 96% | 46 · Fair | 1h 55m |
| 00:15 | 4 | 6h 00m | 96% | 45 · Fair | 2h 00m |
| 00:20 | 4 | 5h 55m | 96% | 45 · Fair | 2h 05m |
| 00:30 | 4 | 5h 45m | 96% | 43 · Fair | 2h 15m |
Each option keeps the wake (or bed) time fixed and moves the other end in 5-minute steps around whole 90-minute cycles, so you wake at the end of a cycle rather than in the middle of deep sleep.
Best option
21:30
6 cycles · Excellent
Time asleep
8h 45m
target 7–9h
Sleep debt vs target midpoint
None
midpoint 8.0h
24-hour view of the best option
Lights out 21:30 · asleep 21:45 · wake 06:30
About this tool
This planner treats a night as a sequence of ~90-minute sleep cycles and finds the times that end a cycle rather than interrupt one, subtracting a realistic sleep-onset latency from the first cycle. Age-band sleep needs come from public sleep-duration guidance and are shown as a range, so the quality rating and the sleep debt figure are comparisons against a general reference, not a diagnosis or a treatment plan. If you regularly cannot sleep, feel exhausted despite enough time in bed, or snore heavily with daytime sleepiness, speak to a clinician. Your last-used settings are kept in this browser's localStorage only.
- 100% free — no account needed
- Runs in your browser
- Nothing is uploaded
Frequently asked questions
Is Sleep Cycle Planner really free?
Yes. Sleep Cycle Planner is completely free on PureBrowser — every feature, with no account, no trial, and no credit card.
Does Sleep Cycle Planner upload my data?
No. Sleep Cycle Planner runs entirely inside your browser, so anything you type, paste, or open stays on your own device.
Do I need to sign up or install anything?
Neither. There is no account and nothing to download — open the page and Sleep Cycle Planner is ready to use on desktop or mobile.
Does Sleep Cycle Planner work offline?
Once the page has loaded, yes. All of the processing happens locally in your browser, so it keeps working without a connection.
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