How to use the sleep cycle calculator
Find wake times that match 90-minute sleep cycles. Enter number of sleep cycles, minutes to fall asleep in the fields above; the sleep duration, total time in bed are computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- c — Number of sleep cycles
- fa — Minutes to fall asleep (min)
Worked example
With number of sleep cycles = 5, minutes to fall asleep = 15 min, the calculator gives sleep duration ≈ 7.5 h; total time in bed ≈ 7.75 h.
Frequently asked questions
What is the formula for the sleep cycle calculation?
Sleep duration (h) = c × 1.5. Total time in bed (h) = ([Sleep duration] × 60+fa) / 60. Here c is number of sleep cycles, fa is minutes to fall asleep (min).
What inputs do I need for the sleep cycle calculator?
You need number of sleep cycles, minutes to fall asleep in min. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.