Time calculator

Writing a duration

Each row is a length of time, not a time of day. Write it as hours:minutes:seconds (1:30:00), as hours:minutes (1:30), or with units (1h 30m, 90 min, 45s, 2 days). A number on its own is hours, so 2 means two hours and 1.5 means one hour thirty minutes.

Watch the two-part form: 1:30 is one hour thirty minutes, not one minute thirty seconds. For that, write 0:01:30 or 1m 30s.

Adding and taking away

Set each row to add or take. Blank rows are ignored, and you can add as many rows as you need. Minutes or seconds above 59 are allowed and carried over, so 0:90 is read as 1:30:00. A row that cannot be read is flagged and left out of the total.

Reading the total

The total is shown as h:mm:ss, in words, as decimal hours and as total minutes and seconds. Hours are not rolled into days, so thirty hours shows as 30:00:00. If you take away more than you add, the total has a minus sign.

Accuracy

Everything is added in whole seconds, so there is no rounding drift from decimal fractions. Only the decimal-hours figure is rounded, to four places.

Typical uses

Adding up track or video clip lengths, flight legs, run splits, or the daily totals from a paper timesheet. To find the time between two clock times, use the hours calculator instead.