From the Excel Help file:
Measurement units and rulers in Excel
Unlike Microsoft Word, Excel does not provide a horizontal or vertical
ruler, and there is no quick way to measure the width or height of a
worksheet in inches. Excel uses characters, points, and pixels as units of
measurement.
The width of cells is displayed in characters and pixels rather than in
inches. When you drag the boundary of a column heading to adjust the width of
a column on the worksheet, a ScreenTip displays the width in characters and
shows pixels in parentheses.
The height of cells is displayed in points and pixels rather than in inches.
When you drag the boundary of a row heading to adjust the height of a row on
the worksheet, a ScreenTip displays the height in points and shows pixels in
parentheses.
An approximate conversion of points and pixels to inches is shown in the
following table.
Points Pixels Inches
18 24 .25
36 48 .5
72 96 1
108 144 1.5
144 192 2
HTH,
Elkar