Microsoft® Excel® 2010 Inside Out

Making Your Custom Functions Available Anywhere

To use a custom function, the workbook containing the module in which you created the function must be open. If that workbook is not open, you get a #NAME? error when you try to use the function. Even with the workbook open, if you use the function in a different workbook, you must precede the function name with the name of the workbook in which the function resides. For example, if you create a function named DISCOUNT in a workbook named Personal.xlsb and you call that function from another workbook, you must type =personal.xlsb!discount(), not simply =discount().

You can save yourself some keystrokes (and possibly some typing errors) by selecting your custom functions from the Insert Function dialog ...