What this calculator does
Time duration arithmetic works out adds and subtracts hours, minutes and seconds. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaConvert everything to seconds, add or subtract, then divide back into h : m : s
The inputs explained
| Field | What to enter |
|---|---|
| Hours | A number. Starts at 2. |
| Minutes | A number. Starts at 45. |
| Seconds | A number. Starts at 30. |
| Operation | Choose from Add, Subtract. |
| Hours | A number. Starts at 1. |
| Minutes | A number. Starts at 50. |
| Seconds | A number. Starts at 45. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with hours
Every other input is held at the calculator’s starting values while hours varies. Select any row to load that scenario into the calculator.