Adding and subtracting hours and minutes
Time does not work in tens, so adding 2 hours 30 minutes and 1 hour 45 minutes by hand means carrying over at 60. The method this tool uses is to convert each duration into total minutes, add or subtract them, and turn the result back into hours and minutes.
In that example, 150 minutes plus 105 minutes is 255 minutes, which is 4 hours and 15 minutes. These are durations (lengths of time), not clock times, so there is no concept of AM, PM or midnight rollover.
Where this comes in handy
Timesheets, shift totals, study logs, cooking schedules, video lengths, and travel legs all involve adding up durations. Subtraction is useful for finding what is left of an allowance, such as how much of a 5-hour budget remains after a 3 hour 20 minute task.
Anyone who has tried to total a week of work entries in decimal hours knows how easy it is to slip, so a dedicated tool is quicker than a calculator.
How to use the time calculator
- Enter the first duration in the first Hours and Minutes boxes. They start at 2 and 30.
- Choose + or the minus option from the dropdown.
- Enter the second duration in the second pair of boxes. They start at 1 and 45.
- The Result appears below, for example 4h 15m.
For subtraction, 1 hour 30 minutes minus 2 hours gives -0h 30m, with a leading minus sign because the second value is larger. There is no button to press, as the answer updates while you type.
Limits and tips
The tool handles exactly two durations at a time. For a long list, add them in pairs and carry the result forward by typing it into the first row. Minutes above 59 are accepted and carried into the hours automatically, so entering 0 hours and 90 minutes counts as 1 hour 30 minutes. Hours are not capped at 24, so a result of 30h 10m stays as it is rather than turning into days.
Seconds are not supported, and negative inputs are treated literally as negative amounts of time, which can be confusing, so stick to positive numbers and use the operator to subtract. Decimal inputs also work arithmetically, but the result can then show fractional minutes. If you want to count days between calendar dates rather than hours, use the Date Calculator.