Time Calculator
Add and subtract hours, minutes & seconds — or find the exact duration between two times.
Time Calculator
Based on your results — what to do next:
Tracking hours for a full pay period?
A 8.5-hour shift is easy to log one day at a time — the Time Card Calculator totals a whole week, including overtime.
Turn hours into pay
Convert an hourly rate into what 8.5 hours (or a full year of them) actually earns you.
Working more than 40 hours a week?
See how time-and-a-half or double-time pay changes your total earnings once weekly hours cross the overtime threshold.
This time calculator has two modes: Add / Subtract Time sums any number of hour, minute, and second values with + or − signs; Time Between Two Times finds the exact duration between a start time and end time, including overnight spans that cross midnight. Every result is shown in H:MM:SS, total minutes, and decimal hours — the format payroll systems use to calculate pay.
How Time Calculations Work
Every time value is converted to total seconds (or total minutes for durations), added or subtracted as plain numbers, then converted back into hours, minutes, and seconds. For durations that cross midnight, 24 hours (1,440 minutes) is added to the end time before subtracting the start time so the result is never negative.
Duration (min) = (End − Start) mod 1,440
Decimal Hours = Total Minutes ÷ 60
| Variable | Meaning | Notes |
|---|---|---|
| H, M, S | Hours, minutes, seconds entered per row | Each row can be added (+) or subtracted (−) |
| mod 1,440 | Wraps duration to a positive value under 24 hours | Handles overnight shifts automatically |
| Decimal Hours | Minutes ÷ 60 | The format used to multiply by an hourly wage |
Worked example: a shift from 9:00 PM to 5:30 AM (next day) is 8 hours 30 minutes = 510 minutes = 8.5 decimal hours. Adding 2h 30m + 1h 45m = 3h 75m, which carries over to 4h 15m (240 + 45 = 285 total minutes, or 4.75 decimal hours).
💡 Pro-Tip
Payroll Runs on Decimal Hours, Not Clock Time: Most payroll systems round to the nearest quarter-hour (0.25) or hundredth (0.01) of an hour — never to raw minutes. A shift of 8 hours 10 minutes is not "8 hours 10" on a paycheck; it's 8.17 decimal hours (10 ÷ 60 = 0.167, rounded). If your actual minutes worked don't match what shows up on your pay stub, check whether your employer rounds to the nearest 15-minute increment — the FLSA allows this as long as it doesn't systematically shortchange employees over time.
Time Calculator FAQ
How do I add times like 2:45 and 1:30?
Enter 2 hours 45 minutes in one row and 1 hour 30 minutes in a second row, both set to "+". The total is 4 hours 15 minutes (45 + 30 = 75 minutes = 1 hour 15 minutes, carried into the hours column).
How do I calculate hours worked overnight?
Switch to the "Time Between Two Times" tab, enter your clock-in time as Start and clock-out time as End, then check "End time is the next day" if your shift crosses midnight. For example, 11:00 PM to 7:00 AM the next day returns 8 hours 0 minutes.
What is 45 minutes as a decimal?
45 minutes ÷ 60 = 0.75. Common conversions: 15 min = 0.25, 20 min = 0.33, 30 min = 0.5, 40 min = 0.67, 45 min = 0.75, 50 min = 0.83.
How is this different from the Time Card Calculator?
This Time Calculator handles one-off math — adding time values or finding the gap between two clock times. The Time Card Calculator is built for a full pay period: multiple clock-in/clock-out pairs across several days, with automatic overtime and gross pay calculations.
Next Step: Related Calculators
Time Card Calculator
Track daily work hours, calculate total weekly hours, and gross pay including overtime.
Hourly to Salary Calculator
Convert hourly wage to annual salary — or annual salary to hourly rate. Includes all pay periods.
Overtime Pay Calculator
Calculate OT earnings at 1.5×, double-time, and blended rates — for hourly and salaried workers.