Check what is in a cell — blanks, errors, numbers, text — and make formulas robust. This page lists all 21 of them; each links to a full lesson with an example you can copy and a practice file.
CELLCELL reports details such as address, column width, number format or file path. Its best-known use is getting…ERROR.TYPEERROR.TYPE returns a number for each error (1 #NULL!, 2 #DIV/0!, 3 #VALUE!, 4 #REF!, 5 #NAME?, 6…INFOINFO returns details like the Excel version, operating system or current folder.ISBLANKISBLANK returns TRUE only for truly empty cells. A formula returning "" is not blank to ISBLANK —…ISERRISERR is TRUE for every error except #N/A. That lets you treat “not found” as normal while still…ISERRORISERROR returns TRUE for any error value. It is mostly used in conditional formatting and checks; for replacing…ISEVENISEVEN returns TRUE for even numbers; ISODD for odd ones. Decimals are truncated first.ISFORMULAISFORMULA returns TRUE when a cell contains a formula. Use it in conditional formatting to catch numbers someone…ISLOGICALISLOGICAL checks whether a value is a real TRUE/FALSE. Imports often bring the text "TRUE", which looks identical…ISNAISNA returns TRUE only for #N/A — the “not found” result — so you can react to missing…ISNONTEXTISNONTEXT is TRUE for numbers, blanks, errors and logicals. Handy in data validation to block text in amount…ISNUMBERISNUMBER returns TRUE for numbers (and dates). Combined with SEARCH or MATCH, it turns “found / not found”…ISODDISODD returns TRUE for odd numbers (decimals are truncated first).ISREFISREF returns TRUE when its argument is a reference. With INDIRECT it checks whether a sheet name typed…ISTEXTISTEXT returns TRUE for text — the quickest way to find numbers or dates that were imported as…NN returns numbers unchanged, TRUE as 1 and text as 0. Its oddest use is hiding a note…NANA produces #N/A deliberately. Charts skip #N/A points instead of plotting them as zero.RTDRTD pulls live values from a real-time data server, e.g. stock prices from a broker's trading terminal add-in.…SHEETSHEET returns the position number of a sheet.SHEETSSHEETS counts sheets in a reference or the whole workbook — including hidden ones.TYPETYPE returns 1 number, 2 text, 4 logical, 16 error or 64 array.