Time Duration Calculator
Find the time between a start and an end clock time, including overnight shifts.
Example · 10:30 PM → 6:15 AM next day = 7h 45m
Time Calculator
Add or subtract hours and minutes across several durations. Negative totals keep their sign.
Your entries stay in this browser
Totals are exact to the minute. See calculation methodology
How to use it
- Input
- 1h 20m + 0h 45m − 0h 30m
- Calculation
- 80 + 45 − 30 = 95 minutes
- Result
- 1h 35m · 1.58 decimal hours
- Input
- 0h 15m − 1h 00m
- Calculation
- 15 − 60 = −45 minutes
- Result
- −0h 45m · −0.75 decimal hours
- Enter hours and minutes for the first duration.
- For each extra duration, choose Add or Subtract, then enter its hours and minutes.
- Use “Add another duration” for up to 20 durations.
- Select Calculate to see the total in hours and minutes and in decimal hours.
How it works
Each duration is converted to whole minutes. Durations are added or subtracted in order, and the total is shown in hours and minutes and in decimal hours rounded to two places.
If you subtract more time than you add, the total keeps its minus sign.
row minutes = hours × 60 + minutes
total = Σ (± row minutes)
decimal hours = total ÷ 60Limitation. Up to 20 durations, each from 0 to 999 hours and 0 to 59 minutes. Totals are limited to 1,000,000 minutes.
Frequently asked questions
What happens if the result is negative?
The total keeps a minus sign. For example, 0h 15m − 1h 00m = −0h 45m.
Can I enter 90 minutes?
Minutes go from 0 to 59. Enter 90 minutes as 1 hour and 30 minutes.
How do I get decimal hours?
The result also shows decimal hours rounded to two places, for example 1h 35m = 1.58. For three or four places, use the Decimal Hours Converter.
How is this different from the Time Duration Calculator?
This tool adds and subtracts lengths of time. The Time Duration Calculator measures the time between two clock times.