Add Hours and Minutes Using Base 60
A duration describes an amount of elapsed time.
Distinguish a duration from a clock time
A duration describes an amount of elapsed time. It can be longer than one day, such as 30:00:00. A local clock reading needs a date and time zone before it identifies an instant. This calculator works with durations only.
Carry sixty minutes into an hour
Adding 2:50 and 1:25 gives three hours and 75 minutes. Converting 60 of those minutes to an hour produces 4:15. Adding the visible digits as decimal numbers would not follow the same rule.
Allow a negative difference
Subtracting 2:00 from 1:15 gives -0:45:00. That result means the first duration is 45 minutes shorter. It is not automatically moved into the next day as an overnight shift might be.
Convert only after totaling
The tool totals whole seconds, then displays decimal hours. For a timesheet, keep the clock-style values during intermediate arithmetic and apply your required rounding policy at the end. A dated shift crossing a clock change requires a separate time-zone calculation.
Put it into practice
Work Hours Calculator
Calculate a seven-day timesheet with unpaid breaks, overnight shifts and totals in hours and minutes or decimal hours.
Time & planningTime Since Calculator
Measure elapsed time from a past date and time to now, with a live counter in total days, hours, minutes and seconds.
Time & planningAdd & Subtract Durations
Add or subtract hours, minutes and seconds without treating them as decimal numbers or clock dates.
Time & planning