# How to Use Excel's FORECAST Function

How to Use Excel's FORECAST Function. Microsoft has built a wealth of powerful functions into its Excel spreadsheet to help users. The FORECAST function is a useful addition that forms forecasted values for use in estimates and projections in a spreadsheeet. The FORECAST function is something you can do to a formula, to program cell values in Excel worksheets for results that you can see in a target cell.

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Open the function bar, a text box with the = sign to the left, that symbolizes the programming of the cell value for your selected cell. For Excel programs that are more guidance-driven, you'll have to open the function bar using "Insert" and "Function" from the menu.

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Start off by including the FORECAST operator.

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Start parentheses. The rest of your equation with be inside parentheses.

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Input your target value for the forecast. This is the X number for which you can expect to get your desired Y value. The FORECAST function returns the corresponding projected Y value for your X number according to logical extension of the value range you program into it.

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Put in your range of Y values. You can enter range of cells, like A2:A7, or a range of values in brackets, like {1,2,3,4,5}.

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Enter a similar array of X values. Remember, the Excel sheet will take all of your X values, and all of your Y values, and project the Y number that will correspond to the X number you provided at the beginning of your equation.

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Close parentheses. You should have a finished FORECAST command. For example, if your X and Y values are included in a set of cells between A2 and B7, your equation would look like this: FORECAST (100, A2:A7, B2:B7).