Data validation

A part of creating efficient and easy-to-use worksheets is to do what you can to ensure that the data entered into the worksheet is as accurate as possible. While it isn’t possible to catch every typographical or transcription error, a validation rule can be set up to make sure data entered into a cell meet certain standards. The Data Validation dialog box is used to define the type of data that Excel should allow in the cell and to set the conditions the data must meet.