Sleep duration calculator
How many hours did I sleep?
Enter when you went to bed and when you woke up to estimate the hours you actually slept, not just the time you spent in bed.
The quick answer
Time in bed is not the same as time asleep
This calculator measures the window between your bedtime and wake time, then removes the minutes you spent drifting off and any stretches you were awake during the night. The remainder is an estimate of actual sleep rather than time spent in bed.
Example: in bed from 11:00 PM to 7:00 AM is eight hours, but with fifteen minutes to fall asleep the estimate is closer to seven hours and forty-five minutes, before counting any night-time waking.
Because cycle length and time awake vary from night to night, treat the hours and the cycle count as planning context. They describe opportunity for sleep, not a measurement of your sleep stages. Read the calculation methodology and limitations.
Planning a night ahead instead of reviewing one? Use the bedtime calculator or the wake-up calculator.
About measuring how long you slept
How many hours did I sleep?
Enter the time you got into bed and the time you woke up. The calculator measures the time in bed, then subtracts your estimated time to fall asleep and any minutes you were awake during the night to show an approximate sleep duration.
What is the difference between time in bed and sleep duration?
Time in bed is the full window between lying down and getting up. Actual sleep is usually shorter because falling asleep takes time and most people wake briefly during the night. This tool reports both so the gap is visible.
Does this work for sleep that crosses midnight?
Yes. If your wake time is earlier on the clock than your bedtime, the calculator treats it as the next morning and the result notes that the window crosses midnight.
How accurate is the cycle estimate?
Cycles are shown as a rough count using a familiar 90-minute approximation. Real cycles vary between people and across the night, so treat the number as a planning aid rather than a measurement of your sleep stages.
Why does it say my times leave no measurable sleep?
That appears when the minutes you remove for falling asleep and being awake are equal to or greater than the time in bed, or when the bedtime and wake time are identical. Adjust the inputs so some sleep time remains.