#units

Deity of Units, Embodiment of Quantum Mechanics.

Species: Cat (Abyssinian)

Likes: Rulers

A point is a typographic measure, coming from 1517, that is supposedly the smallest interesting size for a printer. This was notably not a standardized measure- different companies in times used different point sizes depending on their equipment. Over time it was standardized, but each country picked a different standard: the German and Japanese point is 0.250 mm, the French point is allegedly 0.399 mm, etc.

But early computer history is super Americentric so that's what technology uses. In the US, they standardized the point around the end of the 19th century. To what? I dunno. This source from 1900 gives the length of a point as 35/996 cm (72.281 points/in) and then says there are exactly 867.4699 "ems per foot" (72.289 points/in). This source from 1916 says the standard pica (12 points) is 0.16604 inches and that there are 72.272 "pica ems per foot". Which conveniently enough gives us 72.272 points/in (a pica being 12 points). Then on the very next page they say no a pica is actually 0.166044 inches and a point is exactly 0.013837 inches. I found other sources with other definitions, too.

I'm going to chalk the differences up to a mix of "the definitions of 'meter' and 'foot' changed over time" and "these are less than a micron apart so who gives a shit". I do, I give a shit. Regardless, the official NIST definition settled on a point being 0.013837 inches, so you'd get 72.27 points/inch.

Wrong! You absolute moron. You get 72.270001 points/inch. This annoyed Donald Knuth enough that he rejiggered the ratio in TeX

Physical quantities are measurable properties of objects or phenomena that are expressed using a number and a unit. They form the foundation of physics and help describe everything from motion and force to energy and temperature. Physical quantities are broadly classified into fundamental quantities, such as length, mass, and time, and derived quantities like velocity and force. Understanding…