Time Calculator – Add, Subtract & Convert Time Durations Free
Add or subtract any combination of hours, minutes, and seconds, calculate time between two clock values, and convert between 12-hour and 24-hour formats.
Results
What is this tool?
A free Time Calculator performs arithmetic on time values — adding or subtracting durations, computing the difference between two timestamps, and converting between AM/PM and 24-hour formats. Shift workers use it to calculate hours worked, project managers track task durations, and travellers compute flight times across time zones. All calculations run instantly in your browser without any account or installation.
How to use this tool?
1. Choose the operation: add, subtract, or find the difference between two times
2. Enter the first time value (hours, minutes, seconds)
3. Enter the second time value or duration to add/subtract
4. Click "Calculate" to see the result
5. Toggle between 12-hour and 24-hour format as needed
6. Use the total seconds or decimal hours output for spreadsheet or billing calculations