Error ExplainerAn Excel error value starts with a hash sign and names a kind of problem. The pages below cover the ten you will meet most: #DIV/0!, #N/A, #NAME?, #VALUE!, #REF!, #NUM!, #NULL!, #SPILL!, #CALC! and a row of hash signs in a cell. Every example was typed into a real copy of Excel, and the result shown is what Excel displayed, so you can check your own sheet against it.
The page on Excel error values puts all of them in one table and lists the tools that find the cause.
This is an independent guide. It is not connected with Python, Microsoft, Google, GitHub or the Git project. Product names belong to their owners. Examples were run on 13 November 2026 in a practice folder or a blank workbook; your version may word a message slightly differently.