How to Add Time
Because one hour is equal to sixty minutes, not one-hundred minutes, to add hours and minutes, you need first to convert the minute portion to a decimal number.
To convert the number of minutes to a decimal number, you divide the number of minutes by 60. So if the number of minutes was 15, the decimal equivalent would be 0.25 (15 ÷ 60 = 0.25).
Here is an example of how you would add the following hours and minutes:
| Hours | : | Minutes | Minutes / 60 | HH.HH |
|---|---|---|---|---|
| 3 | : | 12 | 0.20 | 3.20 |
| 4 | : | 15 | 0.25 | 4.25 |
| 2 | : | 45 | 0.75 | 2.75 |
| Total: | 10.20 | |||
To convert the decimal total back to the normal hours and minutes format (HH:MM), you multiply the decimal portion by 60. So in the above example, you would multiply 60 by .20, giving you 10:12 (10 hours and 12 minutes).
Add Hours, Minutes, and Seconds
You can use the following calculator to add hours, minutes, and seconds. The calculator converts all entered hours, minutes, and seconds into seconds, adds up the total seconds, and then converts that result back into hours, minutes, and seconds.