Both relative and absolute cell references are used in Excel formulas to tell the program which cells to use in calculations. However, they behave differently when you copy or fill the formula across other cells.

Relative Cell References:

* Default: These are the most common type of cell reference.
* Behavior: When you copy a formula containing a relative reference, the reference adjusts based on the relative position of the cell being copied to.
* Example: Imagine you have the formula `=A1+B1` in cell C2. This formula adds the values in cells A1 and B1. If you copy this formula to cell D3, it will automatically change to `=B2+C2` because it moves one column to the right and one row down relative to its original position.

Absolute Cell References:

* Created with $ symbol: You can create an absolute reference by pressing F4 after entering the cell address in your formula, or by manually adding a dollar sign ($) before the column letter, row number, or both (e.g., $A$1, A$1, $A1).
* Behavior: Absolute references lock onto the specific cell location regardless of where the formula is copied.
* Example: If you have the formula `=$A$1+B1` in cell C2, it will always refer to the value in cell A1 and add it to the value in B1, no matter where you copy the formula.

Here's a table to summarize the key differences:

| Feature | Relative Reference | Absolute Reference |
|---------------------|--------------------|--------------------|
| Default | Yes | No |
| Adjustment on Copy | Yes (relative to new position) | No (locks to specific cell) |
| Example Formula | =A1+B1 | =$A$1+B1 |

Choosing the Right Reference:

* Use relative references when you want the formula to adjust to different cell positions as you copy it across your worksheet. This is useful for creating consistent calculations across rows or columns.
* Use absolute references when you always want the formula to refer to a specific cell, no matter where it's copied. This is helpful for referencing fixed values or data in another sheet.