| pixels | A pixel (px) is a single "dot" on a computer screen. A screen size of 800x600 will have 800 columns and 600 rows of pixels (480,000 pixels in total) |
| % | Percentage. Percentage values are always relative to another value, such as the dimensions of the parent container. For example, a Horizontal Bar with a width of "100%" placed directly in the "BODY" of an HTML page will expand to fill 100% of the BODY width. A similar bar, with width of "100%", placed inside a TABLE, which in turn only has a width of "500px" will expand to fill 100% of the width of the table (500 pixels) |
| mm | Millimetre (1/100 centimetre) |
| cm | Centimetre (100 millimetres) |
| inches | 1 inch is equal to 2.54 centimetres |
| points | 1 point (pt) is the same as 1/72 inch |
| pica | 1 pica (pc) is the same as 12 points |
| em | 1 em is equal to the current font size of the current element |
| ex | 1 ex is the x-height of a font (x-height is usually about half the font-size) |
These units of measurement should be immediately proceeded by a numeric value, for example "50%", "27pt". Also, decimal numbers are permitted, such as "1.5em". Note, there are no spaces between the value and the unit