Well, you could right click on Calculate Field and go to Batch, which will allow you to enter mulitple inputs, choose the field you'd like to calculate, and then run the tool. You can use the "Fill" option to populate both the Field Name field and the Expression field within the tool.[ATTACH=CONFIG]17610[/ATTACH]Alternatively, use the Feature Class iterator to iterate through your shapefiles in a workspace and then use the Calculate Field tool on the output.[ATTACH=CONFIG]17611[/ATTACH]