Method
How the add time calculator works
Every duration is converted to seconds, added or subtracted according to its sign, and the total is split back into hours, minutes and seconds. Because the work is done in whole seconds, 90 minutes is carried to 1 hour 30 minutes and no rounding builds up across rows. A negative total means more time was subtracted than added.
This tool adds durations. To measure the time between two clock readings, use the hours calculator; to total start and end times across a week, use the time card calculator; and to read 24-hour times, use the military time converter. Other tools are in the time calculators collection.
Example
Add time calculator example
1 hour 45 minutes plus 2 hours 30 minutes is 4:15:00, or 4.25 decimal hours. Subtracting a 20-minute break from that leaves 3:55:00.
FAQ
Add time calculator FAQ
How do I add hours and minutes?
Add the minutes together, carry every 60 minutes into one hour, then add the hours. 1:45 plus 2:30 is 3 hours and 75 minutes, which carries to 4:15.
How do I subtract time?
Switch a row's sign to minus. The calculator borrows across hours and minutes for you, so 3:10:00 minus 0:45:00 is 2:25:00.
Can the result be negative?
Yes. If the subtracted time is larger, the total is shown with a minus sign.
Is this for durations or clock times?
Durations, such as task times, lap times or hours worked. To find the time between two clock readings, use the hours calculator.
How do I convert the total to decimal hours?
The result shows it directly. It is the total seconds divided by 3,600; 4 hours 15 minutes is 4.25 hours.