This Excel tutorial explains how to use Excel IFERROR function for worksheet. IFERROR can be used with vlookup to capture ISNA error. You may also want to read: Check Excel #N/A using ISNA Function What is Excel IFERROR Function? Excel IFERROR Function is an error handling function, if an "Error" is found, then a desired value is returned.  This is a new function introduced in Excel 2007, which means Excel 2003 and prior versions cannot be used. Syntax of IFERROR IFERROR(value,value_if...