When copying cells with formulas, the formula will change Relative to the starting cell.

When copying cells with formulas that contain Absolute references, the formula will not change relative to the starting cell(s). It will always refer to the starting cell(s).

Let’s say you have the formula  =B3*B5 in cell B7 and you copy it to C7 and D7.

Cell C7 will read =C3*C5 and
Cell D7 will read =D3*D5

This is called Relative Cell Referencing.  The formula in the  copy to  cells is  Relative to the originating cell(s).  Most of the time, this is the desired result.

Now let’s change the formula to read =$B$3*B5 in cell B7 and copy it to C7 and D7.

Cell C7 will now read =$B$3*C5 and
Cell D7 will read =$B$3*D5

This is called Absolute Cell Referencing.  The formula in the  copy to  cells is  Absolute to the originating cell.

Typically the dollar sign ( $ ) is placed by toggling the F4 key.  

This concept may be difficult to grasp in narrative format (this page). 

Download and refer to the exercise file for exercises and step-by-step instructions:

Absolute References-Mixed References.xlsx

We have found that many experienced users are already aware of this feature and many other experienced users have not and are awed by the time savings and reduced errors.  Some even consider this a very cool Excel trick.