Time Calculator – Add or Subtract Time

Use this time calculator to add or subtract time durations in hours, minutes, and seconds. Enter two time intervals in H:M:S format to calculate the resulting duration instantly.

How the Time Calculator Works

A time calculator combines or subtracts two time durations by converting each duration to a total number of seconds, performing the selected operation, then converting the result back into the standard H:M:S format.

This approach ensures accurate results and prevents common errors that happen when doing time math manually.

Supported Format (H:M:S)

This tool works with durations written as hours:minutes:seconds. For example:

Tip: Always use two digits per section (e.g., 00:05:09) for the most consistent input.

Common Use Cases for a Time Duration Calculator

Examples of Time Calculations

These examples show why a time calculator is more reliable than manual time arithmetic.

Frequently Asked Questions

Is this time calculator accurate?

Yes. The tool converts durations into seconds, performs the calculation, and converts back into H:M:S format to ensure consistent and accurate results.

Can I subtract time and get a negative result?

No. If Duration 2 is greater than Duration 1, the result is shown as 00:00:00.

What formats are supported?

The calculator supports time durations in H:M:S format (hours:minutes:seconds).

Is this time duration calculator free?

Yes. The tool is completely free and runs directly in your browser.