Time Calculator
Add and subtract spans of time in hours, minutes, and seconds, and read a single signed total.
Enter a duration in hours, minutes, or seconds to see the total.
How to use the time calculator
Each row is a length of time in hours, minutes, and seconds. Pick Add or Subtract for the row, type the figures, and the running total updates as you go. Use the button to stack as many durations as you need.
This tool works with lengths of time, not clock readings. If you want the gap between two clock times instead, like 9:15 AM to 5:45 PM, the time duration calculator is built for that.
Adding and subtracting durations
The total is the sum of every row, with subtract rows taken off. So 2h 45m plus 1h 30m is 4h 15m. Mixed units carry the way you expect: 45m plus 30m rolls past the hour into 1h 15m, so you never have to do the borrow and carry by hand.
A subtract row can pull the total below zero, and the tool shows that with a leading minus, like -30m. That is useful for checking whether you are over or under a budget of time, such as a meeting that ran past its slot.
Hours, minutes, and seconds together
You can mix all three units in one row. The tool reduces everything to seconds, adds it up, then formats the total back into hours, minutes, and seconds. It drops any leading unit that is zero, so a short total reads as 45m rather than 0h 45m 0s.
The result line also shows the total in plain decimal hours and in seconds. To turn a length of time into pay at an hourly rate, the work hours calculator adds a rate on top.
Where adding time helps
Runners add lap splits to check a target pace. Cooks stack prep and cook times to plan a meal. Editors total a string of video clips to see if a cut fits its slot. Any time you are adding or taking away lengths of time, this saves the mental arithmetic.
For a single shift with a start and an end, the hours calculator is quicker, since it reads the clock times directly and subtracts a break.
Frequently asked questions
- How do I add two durations together?
- Leave both rows on Add, then type each length in hours, minutes, and seconds. The total updates as you type. For example, 2h 45m plus 1h 30m comes to 4h 15m.
- How do I subtract one duration from another?
- Set a row to Subtract and the tool takes that length off the total. So 2h minus 1h 30m is 30m. The minus button replaces the need to type a negative number.
- What happens if the total goes below zero?
- The tool shows a negative total with a leading minus, like -30m. This is handy for seeing how far a meeting or task ran over the time you set aside for it.
- How is this different from the time duration calculator?
- This tool adds and subtracts lengths of time, such as 1h 30m plus 45m. The time duration calculator finds the gap between two clock times, such as 9:00 AM to 11:30 AM.
- Can I mix hours, minutes, and seconds?
- Yes. Each row takes all three units at once. The tool adds everything in seconds and then formats the total back into hours, minutes, and seconds, dropping any leading zero unit.