How to Subtract Dates in Excel

Formatting an Excel Cell as a Date:
  • Right click on the cell to be formatted;
  • Select the option Format Cells...;
  • Ensure the Number tab is selected within the dialog box that pops up;
  • Select the option Date from the list of Categories and click OK.

This page shows you how to subtract dates in Excel, by first explaining how Excel dates work, and then providing examples of Excel date subtractions.

Understanding Dates in Excel

If you want to subtract dates in Excel, it helps if you first understand how dates are stored within Excel.

Dates are actually stored as positive integers in Excel. It is only the formatting of an Excel cell that causes a number to be displayed as a date, rather than a simple numeric value.

The numbering system used for Excel dates varies with different computer systems, but most commonly, the numbering system is:

01-Jan-1900 is represented by the number 1
02-Jan-1900 is represented by the number 2
03-Jan-1900 is represented by the number 3
31-Dec-2015 is represented by the number 42369

Because Excel dates are simply integers, you can subtract dates in Excel, in the same way that you can subtract any other integers. The result from the subtraction of any two dates is equal to the number of days between the two dates.

Excel Date Subtraction Examples

The following spreadsheet shows three examples of subtracting dates in Excel.

1Start DateEnd DateDifference
1Start DateEnd DateDifference

Note that, in the results spreadsheet above, the cells in columns A and B are formatted with a date format, but the cells in column C are formatted with the 'General' format.