To copy data validation from one Excel cell or range to another, use the Format Painter or copy the validation rules directly. The simplest method is to select the cell with validation, copy it (Ctrl+C), select the destination cell, then use Paste Special (Ctrl+Shift+V) and check only the "Validation" option before clicking OK. This transfers the validation rules without copying the cell's content or formatting.
Alternatively, you can copy the cell normally with Ctrl+C, select your target range, and use Paste Special with "Validation" selected. For copying validation between different workbooks, the process is identical—just ensure both files are open and navigate between them as needed.
If you need to apply the same validation to multiple non-contiguous ranges, select the first validated cell, copy it, then select all destination cells (holding Ctrl to select multiple ranges), and use Paste Special > Validation.
Another approach is to use the Format Painter tool: click the cell with validation, click Format Painter in the Home tab, then click or drag across cells where you want to apply the same validation. This copies all formatting including data validation rules.
Note that if your validation includes formula-based rules, ensure any referenced cells or ranges exist in the destination workbook, or the validation may reference incorrect cells. You can verify validation rules by selecting a cell and checking the Data tab > Data Validation dialog to see what criteria were applied.