What is “font size”?
Fonts are used in different sizes for different purposes. In printed material and Web pages, bigger font sizes are used for headlines and smaller sizes for the main text. Medium sizes are used for sub-headings and standfirsts – short introductions usually positioned between the headline and the main text.
The size of a font is measured in points. This is a measurement of the height of the characters, not the width, which varies according to the particular character. For instance, the width of an “i” is considerably narrower than the width of an “m”.
I’ll give him lots of points for his height – he’s a lot taller than the other one, who gets just a few points.
There are 72 points in one inch, so 72-point type (usually written 72pt) is exactly one inch high, including the ascender or descender, or the unoccupied vertical space if there is no ascender or descender.
The ascender is the vertical line on, for instance, the letter “h” or “d” (the line goes up, or “ascends”, from the other part of the letter); a descender is the vertical line on, for instance, the letter “p” or “q” (the line goes down, or “descends”, from the other part of the letter).
Normal type sizes for text are 8pt, 9pt, 10pt, 11pt or 12pt, and for headlines it can be anything from 18pt (quite small) right up to 240pt or more (huge) for the front-page headline in a tabloid newspaper.
72pt = 1 inch = 25.4mm