CSS Measurements

emrelative to the height of the font used in the element
example: h1 {margin: 0.5em}

exrelative to the height of the character "x" in font
example: h1 {margin: 1ex}

pxsize in screen pixels
example: p {font-size: 10px}

insize in inches
example: p {font-size: 0.5in}

cmsize in centimeters
example: p {font-size: 0.3cm}

mmsize in millimeters
example: p {font-size: 3mm}

ptsize in point (1pt = 1/72 inches)
example: p {font-size: 12pt}

pcsize in picas (1pc = 12 pt)
example: p {font-size: 1pc}

%percentage value relative to parent element
example: p {line-height: 120%}