Add, subtract, and calculate elapsed time across hours, minutes, and seconds with decimal hour conversions.
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A time calculator performs sexagesimal (base-60) arithmetic on hours, minutes, and seconds. It converts irregular time measurements into normalized decimal hours or standard HH:MM:SS formats for payroll, racing, video editing, and project management.
T_{\text{total}} = \sum (H \cdot 3600 + M \cdot 60 + S)Time values are converted to total base seconds, summed or differenced, then converted back into modulo 60 minutes and hours.
Scenario: A project task took 2 hours 45 minutes on Monday and 1 hour 35 minutes on Tuesday.
Time 1: 2h 45m = 165 minutes.
Time 2: 1h 35m = 95 minutes.
Sum: 165 + 95 = 260 minutes.
260 / 60 = 4 hours and 20 minutes (4.33 decimal hours).
Add minutes together. If minutes exceed 59, subtract 60 from minutes and add 1 to hours. Then add the hours together.
Divide 45 by 60: 45 ÷ 60 = 0.75 decimal hours.
Sexagesimal math is base-60, originating from ancient Babylonians. There are 60 seconds in a minute and 60 minutes in an hour.
Yes, select the Subtract (-) operator to find remaining time or duration differences.
Add and subtract multiple running timestamps, lap splits, or shift durations in a single cumulative timesheet.
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Convert raw seconds into formatted HH:MM:SS, days, decimal hours, and total minutes.
4 hours, 15 minutes, 0 seconds
4.2500
hrs15,300
secs