How to Change the Font Size in a Drop-Down Box With Data Validation in Excel 2007by Darrin Koltow ; Updated February 10, 2017
Changing the font size of a drop-down box produced by Excel's "Data Validation" command is not possible in Excel 2007; however, an equivalent control with data validation does let you change the font size. By changing the size of the fonts used in Excel, you make data entry much easier on the eyes, especially for users with impaired vision. You can change other font characteristics as well, such as font family and color, to make your drop-down list even more readable. In addition, you can change the size of the control itself to better fit the list the control displays.
Type a list of items you want to use for the drop-down list. For example, if you want users to only enter the words "apple," "orange" or "pear," type those items in separate rows in a single column of a worksheet.
Click the "Developer" tab and then click the "Insert" command of the Controls panel. Excel will display a list of controls you can add to your workbook. Click the "ActiveX Combo box" in the lower portion of the list, then drag in the current worksheet to define the combo box.
Right-click the combo box and click "Properties." Excel displays a list of attributes for the combo box. Click in the "ListFillRange" row, which is the cell address from which the combo box creates its drop-down list.
Type in the address of the range continuing the list entries you typed in Step 1. For example, if your list occupies cells A1 through A6, type "A1:A6" in the ListFillRange row.
Click the "Font" item in the Properties pane to open a dialog box in which you can set font properties for the combo box. Type any font size you'd like for the "Size" text box, then click "OK" to install the new size in the combo box.
Click the "Design mode" button of the Controls panel to enter user-entry mode, then click the arrow to the right of the combo box you just formatted. The control will display your list entries in the font size you specified in the previous step.