Time Calculator
Add or subtract hours, minutes and seconds, carrying over correctly.
About the Time Calculator
Enter two durations as h:mm or h:mm:ss and choose add or subtract. The calculator gives the result, the same time in decimal hours and minutes, the total seconds and days and hours.
Time uses base 60 for minutes and seconds, so 45 + 30 minutes is 1 hour 15 minutes, not 75. The calculator converts everything to seconds, adds or subtracts, then converts back.
The formula
Seconds = h × 3600 + m × 60 + s
Worked example
2:45:30 + 1:30:45
- Seconds: 30 + 45 = 75 = 1 min 15 s
- Minutes: 45 + 30 + 1 = 76 = 1 h 16 min
- Hours: 2 + 1 + 1 = 4, so 4:16:15 (4.2708 hours)
Questions people ask
Can the answer be more than 24 hours?
Yes; it's a duration, not a clock time.
How do I add a clock time and a duration?
Enter the clock time as h:mm and add the duration; subtract 24 h if the result passes midnight.
How do I add several times?
Add two, then add the next to the result; or use the Hours Calculator for a list of shifts.