Time Duration Calculator
Free time duration calculator: find the exact hours, minutes, and seconds between a start and end time, or add and subtract time durations.
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Calculate Time Durations Easily
Need to add up work hours, calculate total event time, or find the difference between two durations? Our time duration calculator handles the complex math of hours, minutes, and seconds for you.
Working with Time Durations
Time arithmetic is tricky because it uses base 60 (60 seconds in a minute, 60 minutes in an hour), so adding 45 minutes to 1:30 requires carrying over to hours. This calculator handles those conversions automatically across two modes: 'Between two times' finds the elapsed hours, minutes, and seconds from a start clock time to an end clock time (auto-adjusting when the span crosses midnight), while 'Add / subtract' combines or subtracts durations in hours, minutes, and seconds. Results are shown as h:m:s and as decimal hours for payroll and billing.
Time Conversion
1 hour = 60 minutes = 3600 secondsHow to Calculate Durations
Enter the first duration.
Select add or subtract.
Enter the second duration.
View the result in readable format.
Applications
Exercise
Add times from different physical activities.
Projects
Calculate total time spent on tasks.
Travel
Add segments of a long trip.
Media
Calculate total duration of videos or audio.
Why Use This Calculator?
Automatic Handling
Automatically converts seconds to minutes to hours.
Multiple Inputs
Add multiple durations at once.
Flexible Formats
Work in hours, minutes, or seconds.
Overnight-Aware
Automatically detects shifts that cross midnight and adds a full day, so an overnight span like 22:00 to 06:00 correctly totals 8 hours instead of a negative value.
Two Calculation Modes
Switch between elapsed time (start time to end time) and duration math (add or subtract two durations) in a single tool, so it fits both 'how long between' and 'what's the total' questions.
Frequently Asked Questions
Use the 'Between two times' mode: enter a start time and an end time and the calculator shows the exact duration in hours, minutes, and seconds. If the end time is earlier than the start (an overnight shift), it automatically treats the end as the next day and adds 24 hours. Switch to 'Add / subtract' mode to combine or subtract two durations instead (e.g. 2h 30m + 1h 45m = 4h 15m).
The result will be negative, indicated with a minus sign. This can be useful for knowing how much time is remaining or overdue.
'Between two times' finds the elapsed time from a start clock time to an end clock time — e.g. 9:00 to 17:30 = 8h 30m. 'Add / subtract' combines or subtracts two durations — e.g. 2h 30m + 1h 45m = 4h 15m. Pick the tab that matches your task.
Yes. In 'Between two times' mode, if the end time is earlier than the start (e.g. 22:00 to 06:00), the calculator assumes the end is on the next day and adds 24 hours, so the shift correctly shows 8 hours.
Divide the minutes by 60 and add them to the hours: 8h 30m = 8 + 30/60 = 8.5 hours; 2h 15m = 2.25 hours. Decimal hours are the format most payroll and billing systems expect.