Using the Excel NA Function
SummaryThe Excel NA function returns the #N/A error value. #N/A indicates that no value is available. This function can be used to mark empty cells. This helps to avoid errors when working with formulas when you are missing some information. When a formula refers to a cell containing #N/A it will return the error value.
NA is one of the few Excel functions that does not require any arguments.
Usage NotesNA returns the #N/A error value. You must include an empty parentheses with the function or Excel will not recognize the entry as a function.
You can also type #N/A directly into a cell to produce the same result.