To sum race time splits that are some combination of hours, minutes, and seconds, you can use the SUM function. The formula in cell H5, copied down, is:


Generic formula



Excel times are fractional numbers. This means you can add times together with the SUM function to get total durations. However, you must take care to enter times with the right syntax and use a suitable time format to display results, as explained below.

Enter times in correct format

You must be sure that times are correctly entered in hh:mm:ss format. For example, to enter a time of 9 minutes, 3 seconds, type: 0:09:03

Excel will show the time in the formula bar as 12:09:03 AM, but will record the time properly as a decimal value.

Internally, Excel tracks times as decimal numbers, where 1 hour = 1/24, 1 minute = 1/(24*60), and 1 second = 1/(24*60*60). How Excel displays time depends on what number format is applied.

Use a suitable time format

When working with times, you must take care to use a time format that makes sense to display times that represent durations. 

To access and apply custom time formats, select the cell(s), then use Control + 1 (Command + 1 on a Mac), then Number > Custom.

These are the number formats used in the example shown:

mm:ss // split times
h:mm:ss // total time

If total times may exceed 24 hours, use this format:


The square bracket syntax tells Excel not to "roll over" times greater than 24 hours.

Custom time format for hours, minutes, and seconds

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Dave Bruns

Hi - I'm Dave Bruns, and I run Exceljet with my wife, Lisa. Our goal is to help you work faster in Excel. We create short videos, and clear examples of formulas, functions, pivot tables, conditional formatting, and charts.