Circular reference iteration in Excel allows a cell to refer to its own value in a calculation. This can be useful for creating recursive calculations, such as calculating the sum of a range of cells that includes the cell itself. To use circular reference iteration, you must first enable it in the Excel Options dialog box. Once it is enabled, you can create a circular reference by entering a formula that refers to the cell itself. For example, the following formula calculates the sum of the range A1:A10, including the value in cell A1 itself:
=SUM(A1:A10)
