Baby Sleep Duration Calculator
Quickly calculate the elapsed time between a sleep session’s start and end.
For overnight sleep, select the next day as the end date. Times use your device's time zone.
Times stay in this browser tab. They are not saved or uploaded. This tool calculates elapsed time; it does not recommend sleep schedules.
Calculate overnight sleep
Choose the actual starting date and ending date. For example, a sleep session beginning one evening and ending the next morning needs two different dates.
What happens when the clocks change?
The calculation uses your device’s time zone and includes daylight saving changes. A time skipped when clocks move forward is invalid. During the repeated autumn hour, the earlier occurrence is used; a date and time alone cannot distinguish the two occurrences. Use a record with a time-zone offset if that distinction matters.
Want to keep a daily sleep log?
Newbornly offers an easy-to-use sleep timer and daily timeline so you can keep your baby’s recorded sessions together.