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Both calculators run independently β€” change the inputs on either side to compare results.

Sleep

Sleep Cycle Calculator

Find your ideal bedtime by working backward from your wake-up time in complete 90-minute sleep cycles. Waking at the end of a cycle (rather than mid-cycle) leaves you feeling more refreshed than the same total hours timed less carefully.

Fill in the required fields to see your result.
Sleep

Sleep Efficiency Calculator

Measure what percentage of your time in bed is actually spent sleeping β€” a key clinical marker of sleep quality used in insomnia diagnosis and treatment. Efficiency above 85% indicates healthy sleep; under 80% suggests insomnia or fragmented sleep that warrants investigation.

Fill in the required fields to see your result.

Key differences

Sleep Cycle CalculatorSleep Efficiency Calculator
CategorySleepSleep
Inputs required22
ResultOptimal Bedtime (hours)Sleep Efficiency (%)
What it doesFind your ideal bedtime by working backward from your wake-up time in complete 90-minute sleep cycles. Waking at the end of a cycle (rather than mid-cycle) leaves you feeling more refreshed than the same total hours timed less carefully.Measure what percentage of your time in bed is actually spent sleeping β€” a key clinical marker of sleep quality used in insomnia diagnosis and treatment. Efficiency above 85% indicates healthy sleep; under 80% suggests insomnia or fragmented sleep that warrants investigation.