Time Duration Calculator

1. 1Choose Between times, Add / subtract, or Add up.
2. 2Enter the times, or a duration such as 3h 45m, 2:30 or 90 (minutes).
3. 3For a list, put one duration per line and say whether 1:30 means hours:minutes or minutes:seconds.
4. 4Read the result in hours and minutes and in decimal hours.

Between two times, the start is subtracted from the end. If the end is earlier than the start, it is taken to be the next day, so 22:00 to 06:00 is 8 hours.

Adding or subtracting works in minutes and wraps round midnight, saying when the result falls on the next or previous day: 22:30 plus 3 hours 45 minutes is 02:15 the next day.

Durations can be typed as 1:30:15, 1:30, 1h 30m, 90m, 45s, 1.5h or a plain number of minutes. A two-part value like 1:30 is ambiguous — hours and minutes for timesheets, minutes and seconds for music and video — so you choose which.

Totals are added in seconds and only rounded for display. Decimal hours divide by 60: 45 minutes is 0.75 hours, not 0.45.

Adding 1:45, 2:30, 0:50 and 1h 15m

1. 105 + 150 + 50 + 75 = 380 minutes
2. 380 minutes = 6 hours 20 minutes
3. 6 h 20 min = 6.33 hours

Result: 6:20 in total, or 6.33 decimal hours.

• Use decimal hours on timesheets that ask for hours as a number.
• For a whole week of shifts with breaks and overtime, use the Time Card Calculator.
• Write durations with units (1h 30m) when sharing them, to avoid the 1:30 ambiguity.
• Check that times use the same time zone before subtracting them.