To do this the formula is similar to the one for when dates are in the future, it is just tweaked a bit to show the difference. You are subtracting the date in the past from today’s date.

This tutorial will show you how to create a Formula to Add, Subtract, Multiply or Divide in Microsoft Excel. You can do basic calculations easily!

How to subtract in Excel using cell references You don't have to subtract numbers in a single cell; you can also set up a formula that will subtract the values stored in multiple cells.