An error checker identifies spreadsheet errors by traversing a spreadsheet cell-by-cell and comparing each cell's contents to a list of error rules. When a cell's contents satisfy an error rules, then the cell is identified as containing a potential spreadsheet error. The error checker identifies potential spreadsheet errors and marks the cells containing the potential errors with an error indicator. A drop-down menu is provided that includes an element identifying the error rule that was invoked by the cell's contents and may include one or more recommended actions to resolve the identified error.