What is IS function in Excel? IS functions, ISBLANK, ISERR, ISERROR, ISLOGICAL, ISNA, ISNONTEXT, ISNUMBER, ISREF, ISTEXT are under the Information functions in Microsoft Excel. Each of these functions, referred to collectively as the IS functions, checks the specified value and returns TRUE or FALSE depending on the outcome. For example, the ISBLANK function returns the logical value TRUE if the […]