Time Adder / Subtractor

Add and subtract durations

Adding times is awkward because minutes and seconds roll over at 60, not 100. This calculator does the maths for you. Type one duration per line in h:mm:ss or h:mm format and the running total appears instantly. Start a line with a minus sign to subtract it, or with a plus sign (optional) to add it. The default example shows 1:45:30 plus 0:20:15 minus 0:05:00.

The result is shown as hours, minutes and seconds, and also as decimal hours, total minutes and total seconds, so you can copy whichever format your spreadsheet, invoice or timesheet needs.

Typical uses

Editors add clip lengths, runners add split times, musicians total track durations for an album, freelancers add up work sessions, and students check how long a series of lessons will take. Because you can subtract too, you can also work out a remaining duration, such as a two-hour budget minus the time already used.

Negative totals are supported and are shown with a minus sign. If a line cannot be understood, the tool tells you which line has a problem and still adds the valid ones.

Input rules

Use a colon between parts. With two parts the values are read as hours and minutes, so 1:30 means one hour thirty minutes. With three parts they are hours, minutes and seconds. Minutes and seconds above 59 are accepted and carried over. Your list can be saved as a local draft and everything runs in your browser; nothing is uploaded.

To total a long list, paste it from a spreadsheet or notes, one duration per line. You can mix formats freely, for example a video length such as 45:10 should be written as 0:45:10 so it is read as minutes and seconds. Results update as you type, so you can experiment freely and watch how each line changes the total before you copy it.