Date & Time
Time Duration Calculator
This calculator finds the duration between a start time and an end time, useful for tracking work shifts, event lengths, or any span of time measured by the clock rather than the calendar.
The formula
duration = end time − start time (add 24 hours if the end time is earlier)
Worked example
A shift from 9:00 AM to 5:30 PM:
duration = 17:30 − 9:00 = 8h 30m
Frequently asked questions
How is the duration between two times calculated?
The calculator converts both times to minutes since midnight, finds the difference, and converts that back into hours and minutes.
What happens if the end time is earlier than the start time?
The calculator assumes the end time falls on the next day and adds 24 hours before calculating the difference — useful for overnight shifts or events that cross midnight.
Can I use this to calculate work hours?
Yes — enter your clock-in and clock-out times to get total hours worked. If you had an unpaid break, subtract that separately from the result.