Units of Measure

to be used with Cascading Style Sheets

Units for defining length and width
Absolute Units Abbreviation
inches (2.54 cm)
<p style="border-top-width: '1in'">
in
centimeters
<p style="border-top-width: '1cm'">
cm
millimeters
<p style="border-top-width: '1mm'">
mm
points
<p style="border-top-width: '1pt'">

Point and Pica are typesetters units of measure. 12 points are equal to 1 pica. 6 picas is roughly equal to 1 inch. Therefore 72 points are roughly equal to one inch.

pt
picas
<p style="border-top-width: '1pc'">
pc
Relative Units Abbreviation
mutt
<p style="border-top-width: '1em'">

A "mutt" defines the space occupied by the capital letter "M" of the selected font. It is usually (not always) divided into 18 parts. I can find no reference to the degree that a mutt can be used. i.e. 1/18th of a mutt. I have only seen "0.5em" used.

em
x
<p style="border-top-width: '1ex'">

The "x" height is the height of the lower-case "x" in the selected font. I can find no reference to whether or not it can be used in fractions.

ex
pixel
<p style="border-top-width: '1px'">

A pixel is relative to the size of the canvas (the selected browser window)

px