Measure the time between two clock times, or add up a list of durations, and get the answer in hours and minutes, decimal hours, and minutes.
| Line | Read as | h:mm:ss | Decimal h |
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This time duration calculator does two jobs. The first tab measures the elapsed time between two clock times, such as 09:00 to 17:30, with an option for spans that cross midnight and a break deduction, and reports the answer as hours and minutes, decimal hours, total minutes, and seconds. The second tab adds up a list of durations typed one per line in whatever format you have (1:30, 1h 30m, 90m, 2.5h, 0:45:30) and returns the total in h:mm, decimal hours, minutes, and days plus hours. It is meant for timesheets and payroll, billing in decimal hours, editing and media work, travel planning, and anyone who needs to add times without converting to minutes by hand.
Clock times are converted to seconds since midnight. If the end time is earlier than the start and the overnight option is on, 24 hours are added before subtracting; a break in minutes is then removed. Each line in the list is parsed by a small grammar that accepts colon notation (h:mm or h:mm:ss), unit suffixes (h, hr, hours, m, min, minutes, s, sec, seconds) in any combination, decimals (1.5h), and a leading minus sign to subtract. Bare numbers are read as minutes. Totals are summed in whole seconds, so there is no floating-point drift, and decimal hours are simply seconds divided by 3,600.
Type the start and end times as they read on the clock, for example 22:00 and 06:00. With the overnight option on (the default), an end time earlier than the start is treated as the next day, so 22:00 to 06:00 gives 8 hours. Turn the option off if you want a negative result to flag a mistyped time.
One duration per line. Colon notation such as 1:30 (1 hour 30 minutes) or 0:45:30 (45 minutes 30 seconds); words or letters such as 1h 30m, 2 hours 15 min, 90m, 45s; decimals such as 1.5h or 0.25 hr; and bare numbers, which are read as minutes. Start a line with a minus sign to subtract it. Blank lines are ignored and unreadable lines are listed so you can fix them.
Decimal hours are total minutes divided by 60, so 7 hours 30 minutes is 7.5 and 7 hours 20 minutes is 7.333. Payroll systems usually round to two decimals (7.33) or to the nearest tenth (7.3); the tool shows three decimals so you can apply whichever rule your employer uses.
With two parts the tool reads colon notation as hours:minutes, which is the timesheet convention. Use three parts (0:01:30) or unit suffixes (1m 30s) when you need seconds. The parsed meaning of every line is shown in the breakdown table so you can confirm the interpretation.
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