StandardWidth Property
Returns or sets the standard (default) width of all the columns in the worksheet. Read/write Double.
Remarks
One unit of column width is equal to the width of one character in the Normal style. For proportional fonts, the width of the character 0 (zero) is used.
Example
This example sets the width of column one on Sheet1 to the standard width.
Worksheets("Sheet1").Columns(1).ColumnWidth = _
Worksheets("Sheet1").StandardWidth