Point (typography)

The point is the smallest whole unit of measure in typography. It is used for measuring font size, leading, and other minute items on a printed page. Different points have been used since the 18th century, with measures varying from 0.18 to 0.4 millimeters. Following the advent of desktop publishing in the 1980s and '90s, the importance of digital printing supplanted the letterpress printing systems around the world and established the DTP point as the de facto standard. This measures ¹⁄₇₂ of the international inch (about 0.353 mm) and, as with earlier American points, is considered ¹⁄₁₂ of a pica.

In metal type, the point size of the font described the height of the metal body on which the typeface's characters were cast. In digital type, letters of a font are designed around an imaginary space called an "em square". When a point size of a font is specified, the font is scaled so that its em square has a side length of that particular length in points. Although the letters of a font usually fit within the font's em square, there is not necessarily any size relationship between the two, so the point size does not necessarily correspond to any measurement of the size of the letters on the printed page.