Sleep Calculator

Work backward from a wake-up time in approximate 90-minute sleep cycles. It is a scheduling aid, not a measure of sleep quality or medical sleep advice. Calculate it clearly with Figur.

How the sleep calculator works

Work backward from a wake-up time in approximate 90-minute sleep cycles. It is a scheduling aid, not a measure of sleep quality or medical sleep advice.

Method and assumptions

Figur applies straightforward arithmetic to the values you enter. The calculation runs locally in your browser and is not stored.

  • The result depends on accurate inputs and units.
  • External factors, fees, taxes, or rules not requested by the calculator are not included.
  • Use the result as a planning estimate and verify any high-stakes decision.

Sources and references

No external data source is required: this calculator uses standard arithmetic and the values you enter.

Worked example

You want to wake at 7:00 AM and plan 5 cycles.

Aim to be asleep at 23:30; allow your usual time to fall asleep.

Frequently asked questions

Are sleep cycles always 90 minutes?

No. Cycle length varies by person and through the night; 90 minutes is a useful planning approximation.

How much sleep do adults need?

Many adults need 7–9 hours, but individual needs vary. Seek care for persistent sleep concerns.

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