A quick recap on the $ signs in formulas
When a formula references another cell, that cell reference has a column letter and a row number, for example, A1 or CX216. If a formula with a cell reference is copied, you can control how that cell reference behaves. You can make it point to the exact same cell, or you can let it adjust when the formula is copied. To do that, you can use the $ signs in the cell reference. Here’s how they work.
The $sign in a cell reference locks it, so it won’t change when copied down or across. The $ sign can be applied to the column letter, the row number, or both.
The reference A1 copied down will become A2. Copied across, it will become B1. Both the column letter and the row number are relative and will change when the formula is copied.
Lock in the column letter only (mixed reference)
The reference $A1 copied down will become $A2. Copied across, it will be $A1. The column letter is now fixed (absolute) and will not change when the formula is copied.
Lock in the row number only (mixed reference)
The reference A$1 copied down will be A$1. Copied across, it will be B$1. The row number absolute and will not change when the formula is copied.
The reference $A$1 copied down or across will be $A$1. Neither row number nor column letter in an absolute reference will change.
Quickly change the reference type
When you edit a formula you don’t have to type the $ signs manually. Often it is quicker to let Excel do that work. Place the cursor inside or just behind a cell reference and hit the function key F4 on your keyboard. Each press of this key will change the reference type. From relative to absolute to locked row to locked column.
Try it yourself
Here is a sample file. Four different ways to write a formula that references cell A1. Each time, the formula has been copied down two rows and then across two columns. Note that the F4 function key only works if the file is open in Excel for desktop, not in Excel online in the browser.