Time Duration Calculator

Calculating time by hand is error-prone. Converting between hours, minutes, and seconds, or adding multiple durations, leads to mistakes. A time duration calculator does the math instantly and shows the result in multiple units.

Use it for work hours, project time tracking, meeting length, travel time totals, or any scenario where you need to combine or compare time spans. The tool runs in your browser with no sign-up required.

When you have a start and end time (e.g. 9:00 AM to 5:30 PM), use the 'Between times' mode. The tool computes the difference — 8 hours 30 minutes in that example.

When you have multiple durations to combine (e.g. 2h 15m + 1h 45m + 30m), use the 'Add durations' mode. Enter each duration and get the total. Use 'Subtract' for durations to remove (e.g. total work minus break time).

The result is shown in seconds, minutes, hours, and days. Seconds are the base unit — precise and useful for programming or precise tracking. Minutes and hours are human-friendly. Days help when dealing with multi-day spans (e.g. 2.5 days). The HH:MM:SS format is standard for time display and easy to copy into spreadsheets or reports.