Calculate∑ What your result means
Sleep tends to move through cycles of roughly 90 minutes, and waking up at the end of a cycle (rather than in the middle of one) is commonly associated with feeling more refreshed.
Sleep Cycle Bedtime Calculator
Work backward from your wake-up time to find bedtimes that align with full 90-minute sleep cycles.
Your details
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Verified for 2026-27Methodology 2026-27.1 · reviewed 2026-08-08 · review by 2027-03-01
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Compare scenarios
Change wake-up time (24h, e.g. 7 = 7:00am, 19 = 7:00pm) to see the effect on your result.
Understand your result
Clear context for the values above.
Wake-up time
Wake-up time is included so you can interpret this estimate and make a better-informed comparison.
Typical time to fall asleep
Typical time to fall asleep is included so you can interpret this estimate and make a better-informed comparison.
Recommended bedtime
Recommended bedtime is included so you can interpret this estimate and make a better-informed comparison.
Earlier option
Earlier option is included so you can interpret this estimate and make a better-informed comparison.
How to use this calculator
- 1Enter your current wake-up time (24h, e.g. 7 = 7:00am, 19 = 7:00pm), typical time to fall asleep.
- 2Review the headline recommended bedtime (5 cycles / 7.5 hrs) and the supporting figures beside it.
- 3Change one input at a time to see which assumption has the biggest effect.
- 4Confirm current UK rates and thresholds with an official source before acting.
Explore this calculator
What your result means →The headline recommended bedtime (5 cycles / 7.5 hrs) is based on the inputs currently shown above.Key terms explained →Review the assumptions, applicable rules, timing and real-world fees before making a decision.How to use this calculator →Enter your figures, review the live result, compare scenarios, then save or print your estimate.The calculation formula →The calculation follows the standard relationship between the displayed inputs. Results update whenever an input changes.Worked example →Using the current values produces 11:16 PM.Assumptions and limitations →Review the assumptions, applicable rules, timing and real-world fees before making a decision.Costs or factors not included →Review the assumptions, applicable rules, timing and real-world fees before making a decision.Frequently asked questions →How accurate is this estimate? What should I check before relying on it? Can I save or share the result?
▦ How this calculator works
The calculator works backward from your wake-up time in blocks of 90 minutes (for 4, 5 and 6 full cycles), then subtracts your typical time to fall asleep to suggest bedtimes that land you at the end of a cycle.
◇ Assumptions and what's not included
Actual sleep-cycle length varies by person and by night (typically 70–120 minutes), and this is a general rule of thumb rather than a measurement of your own sleep architecture, which only a sleep study can determine precisely.
▤ What to do next
Try the 5-cycle bedtime first, and adjust up or down based on how you actually feel on waking over a week or two, since individual variation matters more than the exact formula.
UK-specific contextFigures use GBP and current published rates and thresholds.
Reviewed for clarityUpdated 3 August 2026.
ImportantFor planning and educational use — not tax, legal or financial advice.
Your privacy mattersInputs stay in your browser.
Frequently asked questions
Is 90 minutes the exact length of every sleep cycle?+
No, it's a commonly used average — individual cycle length varies and can range from about 70 to 120 minutes, and can shift across the night.
Why would I want to wake up at the end of a cycle?+
Waking during deep sleep (mid-cycle) is commonly associated with grogginess, while waking near the end of a cycle, closer to lighter sleep, is often reported as feeling easier.
How many sleep cycles should I aim for?+
Most adults need around 5 cycles (roughly 7.5 hours) for a full night's rest, though individual sleep needs vary — the calculator also shows 4 and 6 cycle options.
Does this replace medical advice for sleep problems?+
No, if you have ongoing sleep difficulties, speak with a GP — this is a general planning tool, not a diagnostic one.
Official references
Rules and thresholds used by this calculator are labelled for 2026–27 or formula-labelled period. Review the primary guidance before making a filing, borrowing, benefit or investment decision.
Last source review: 3 August 2026. Calculator results are estimates and may exclude circumstances described in the methodology.