Time Calculator
Add or subtract hours, minutes and seconds, or shift a clock time. Copy a result you can check.
Your result
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Enter your time and choose Calculate.
Your result
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Enter your time and choose Calculate.
Hours and Minutes Calculator
Use this time calculator online to add hours and minutes from separate tasks, or subtract time you do not need to count. Each row is a duration, so a total can be longer than 24 hours.
- Enter hours and minutes in each row. Show seconds when needed.
- Choose + or −, then select Calculate.
- Check the equation and copy the result, decimal hours and total minutes.
One rule, three units
Seconds = hours × 3600 + minutes × 60 + seconds
Decimal hours = total seconds ÷ 3600
Total minutes = total seconds ÷ 60
Adding Time: Worked Examples
Add time
2:45 + 1:30 = 4:15
45 + 30 minutes makes 75 minutes: carry one hour and keep 15 minutes.
Subtract time
1:00 − 1:30 = −0:30
Subtracting a longer duration gives a negative result. It does not wrap around a clock.
Add several durations
10:20 + 8:40 + 6:00 = 25:00
The time adder keeps all 25 hours, rather than changing the result to 1:00.
Clock Calculator: Add or Subtract Time
Choose Clock time ± duration when you know a starting clock time. Add or subtract a duration to calculate the new time and its day change.
For example, 11:30 PM + 2 hours 45 minutes gives 02:15 on the next day. Subtracting one hour from 00:30 gives 23:30 on the previous day.
Clock time or duration?
A clock time is a position within a day. A duration is an amount of time. This online time calculator keeps the two separate.
For the interval between two clock times, open the time duration calculator.
Time Math: Carrying and Borrowing
Why 7:30 is not 7.30 hours
Time uses 60 minutes per hour. Half an hour is 30 minutes, so 7 hours 30 minutes is 7.5 decimal hours. Decimal 7.30 means 7 hours 18 minutes.
This minutes calculator accepts whole minutes from 0 to 59 in each row. For 90 minutes, enter 1 hour and 30 minutes.
What this calculation covers
Use the time addition calculator for durations and the clock mode for clock arithmetic. Dates, daylight saving changes and time zones can change real elapsed time; they are not part of these calculations.
For seven days of work, use the time card calculator. For a conversion, use hours to decimal.
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