How does Excel deal with hours over 24

Excel doesn't display hours over 24 by default.

But, if you change one option in the number format, you can display hours over 24.

Difference between hours and days in Excel

Rule 1 : A whole number is a day

Rule 2 : A decimal number, between 0 and 1, is a time

Let's consider the value 0.5, and convert it into Time format. Excel displays 12H

This is easy to understand because 0.5 is half of 1. So because 1 is 1 day, 24 hours, 0.5 is 12H 😉

Convert whole number to decimal number

If you have created an Excel worksheet with whole number that represent hours, you MUST convert them.

The first solution is to apply this formula

=<<your value>>/24

The second solution is to use the paste special tool, division option, to convert our whole number 😀😍👍

Have a look at the tutorial video:

Why Excel doesn't display over 24 hours ?

In this example, all the values are in hour format (in decimal number).

The SUM of all the cells returns a value greater than 1 (general format).

But now, if you convert this result into Time format, you don't see the result with values over 24 hours.

The reason it's because after 23:59:59, it's 1 day. So Excel converts the result in days for the whole number and hours for the rest.

Display hours over 24

To display hours over 24 you must customize your number format with brackets.

Open the custom number format.

  • By using the shortcut Ctrl+1
  • Or, by selecting the last menu in the dropdown Number Format list

In the dialog box Format Cells, write the following code with the hour code between brackets.


  • The h between bracket means the hours over 24 hours
  • The mm means the minute format
Hours over 24

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