Enter a start and an end time. You get the duration in hours and minutes and in decimal hours, with an optional break taken off. Overnight times work too.
How the duration is worked out
Both times are turned into minutes after midnight. The start is taken from the end; if the answer is negative, the end must be on the next day, so 24 hours (1,440 minutes) is added. Finally the break is subtracted and the minutes are turned back into hours.
Duration = end − start (+ 24 h if the end is earlier) − break
Minutes to decimal hours
Minutes
Decimal hours
5 minutes
0.08
10 minutes
0.17
15 minutes
0.25
20 minutes
0.33
25 minutes
0.42
30 minutes
0.50
35 minutes
0.58
40 minutes
0.67
45 minutes
0.75
50 minutes
0.83
55 minutes
0.92
Decimals are rounded to two places. 20 minutes is exactly one third of an hour (0.333…).
Questions people ask
How do I calculate hours worked?
Subtract the start time from the end time, then take off any unpaid break. For example, 8:30 a.m. to 5:15 p.m. is 8 hours 45 minutes; minus a 30-minute lunch, that is 8 hours 15 minutes, or 8.25 hours in decimal.
What if the shift goes past midnight?
If the end time is earlier than the start time, the calculator assumes the shift ended the next day. 10:00 p.m. to 6:00 a.m. is 8 hours.
How do I convert minutes to decimal hours?
Divide the minutes by 60. 15 minutes is 0.25 hours, 20 minutes is 0.33, 45 minutes is 0.75. The table on this page lists every five-minute step. Payroll systems usually want decimal hours, because 7.5 hours can be multiplied by an hourly rate and 7:30 cannot.
Does daylight saving time change the result?
This calculator measures clock time on a single night, without dates, so it does not adjust for the one night a year when clocks jump forward or back. A shift across that change is one hour shorter (in spring) or longer (in autumn) than the clock times suggest.