Most printers offer a much higher resolution (300 or 600 dots per inch) than a computer screen (72 dpi). Therefore, information that is displayed on the screen is rendered differently than the printed output. When you select a column or row, and then use the AutoFit command, the font metrics that are used on the screen are different than the metrics the printer uses; some characters for some fonts may use a fractional value.
For example, a font may report 9.1 pixels, but because a display driver is unable to work with fractional amounts, it rounds the amount to the nearest whole pixel value. In this example, 9.1 pixels is rounded down to 9.0 pixels. When a higher resolution printer renders the view in print preview or is used when you print the worksheet, the characters may be printed at a resolution of 9.1 pixels. Because the column width is calculated based on the rounded whole number value, the printed output of the column width is different from the displayed column width. This discrepancy is particularly apparent when you use the AutoFit command to resize columns that contain long text strings.