fonts What is a typographic point?

You’ve probably written enough documents in a word processor that you’ve never really thought about “font size.”

The standard recommendation is usually to write text at “11” or “12” size, depending on the font. For example, you might write serif fonts at size 12, and sans serif fonts at size 11, because sans serif fonts like Arial tend to appear larger than serif fonts like Times. The number is actually a typographic point and measures exactly 1/72 of an inch.

Early European type

When movable type was new, printers needed a way to consistently measure distances in type. A French priest named Truchet studied printmaking and typefaces, and used the French line, derived from silversmithing, to measure different type styles. The line was 1/12 of a French inch. Later, to more accurately describe the curves of fonts using mathematics, Truchet divided the line further into a point, which was 1/12 of a line or 1/144 of a French inch.

This proved to be too detailed for crafting fonts using the methods of the day, so Truchet’s point measurement didn’t gain traction. However, another typographer named Fournier defined a similar point, but at 144 points over 2 inches, or 1/72 of an inch.

Another French printer named Didot improved on the Fournier system in the late 1700s. While Didot’s point used the same definition of 72 points per inch used by the Truchet system, Didot’s measurement was based on the royal foot, so was a slightly different length.

American style

In the late 1700s, the American print industry used the pica as the standard measurement. The pica is 1/6 of an inch, and remained a common measurement for print into the Twentieth Century, although you may not know it by name. For example, printers and typewriters often produced text lines that were 1 pica high; that’s why a typewriter, TeleType, or old-style dot-matrix printer produced 66 lines of text on a US Letter page at 11 inches.

American printer Benjamin Franklin encouraged his grandson to enter printmaking, and imported French printing machinery and type foundries into the US. Franklin also arranged for his grandson to study under French printer Didot. By doing so, Franklin imported the point into US printing: 72 points to 1 inch.

Digital type

When we started generating print content using computers, the point became a convenient measurement. In the modern desktop computing era, print at “12 point” became the norm for academic printing. You can often find reference to “Times at 12 point” for some academic paper style guides.

Point sizes for most “everyday” print needs are 9, 10, 11, 12, 14, and 16. The smaller font sizes like 9 point and 10 point text are excellent for captions and footnotes. Larger font sizes like 14 point and 16 point work well for section headings and other title text. You might use very large font sizes like 36 point, 48 point, or 72 point when working with large format print projects such as posters and fliers. Here are several common font sizes, in both points and inches:

100.13888…just under 1/7
110.152777…just over 1/7
140.19444…just under 1/5

Notice that 12 point type is 1/6 of an inch. That’s 1 pica! And while I can’t locate research on this, I suspect that one reason “12 point” has remained a popular font size—especially in academia—is because pica-sized type was very popular in early US printing. Interesting how these old standards continue to modern times.