Define the default column width

Right-click a sheet tab, and then click Select All Sheets on the shortcut menu

On the Format menu, point to Column, and then click Standard Width.

Type a new measurement.

The number that appears in the Standard column width box is the average number of digits 0-9 of the standard font that fit in a cell.

To define the default column width for all new workbooks and worksheets, create a workbook template and a worksheet template.