# Add or subtract time

You can add and subtract time in Excel almost like you subtract other types of numbers. For example, you might do this if you want to know how long it took to complete a project’s tasks. The one exception is that Excel doesn't support a negative number formatted as time.

## Inside this course:

**Add time**** ****(****3:33****)**The best way to add time is to use the AutoSum button on the Home tab. You can also add a unit of time, such as 1½ hours, to a time of day, such as 10:00 a.m., by using the TIME function.

**Subtract time**** ****(****4:06****)**You can subtract time in Excel almost like you subtract other types of numbers. To do this, you use a formula; there isn’t an AutoSubtract button. Like with adding time, you can also subtract a unit of time, such as 1½ hours, from a time of day, such as 10:00 a.m., by using the TIME function.

**Course summary**** **A brief reminder of the key points in this course.

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