Calculators

Time Duration Calculator

Add and subtract elapsed durations with exact millisecond totals, including totals longer than 24 hours.

Use H:MM or H:MM:SS, optionally with .mmm after seconds. Example: 2:15 means 2 hours 15 minutes; 0:00:01.250 means 1.250 seconds. Prefix a line with - to subtract it. Up to 200 entries.

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Add or subtract durations

Enter one elapsed duration per line. Positive entries add time; a leading minus sign subtracts time. Blank lines are ignored. Select Calculate total duration, then copy or download the result.

Use H:MM for hours and minutes, or H:MM:SS for hours, minutes and seconds. Seconds may have one to three decimal places. Minutes and seconds must use two digits from 00 to 59. Hours may have up to nine digits. A two-part entry such as 1:30 means one hour and thirty minutes.

The clock-style total and millisecond total are exact. Decimal hours and minutes are rounded to six decimal places. The total can exceed 24 hours or be negative. This tool adds durations; it does not calculate dates, time zones or daylight-saving changes.

Example

1:30:00 + 0:45:30 − 0:15:30 = 2:00:00. The calculation runs in your browser.