There are times when you may not want the cell reference to automatically change relative to the new location. In this case, you simply adjust your cell references to Absolute Cell References. An absolute cell reference looks just like a relative cell reference with the addition of dollar signs ($).For instance, when you copy a formula with absolute cell references, the new formula references remain unchanged. So, in this case, a cell that originally read: =$B$1+$C$1, would read, after copied: =$B$1+$C$1.
Let me explain this another way. An absolute cell reference is a reference to a cell that always refers to one specific location. So, if the position of the cell that contains the formula changes, the absolute reference remains the same. This means that the act of copying a formula or using AutoFill will not change the formula regardless of the new formula location.
Changing a Cell Reference From Relative to Absolute
Select the cell that contains the formula you want to copy
Press F2 to edit the formula (Or, you can use the Formula Bar)
Position your cursor in the middle of a cell reference (if your reference is B1, the cursor should be blinking in between the B and the 1)