The Diatonic Scale of Type

"The simplest scale is a single note, and sticking with a single note draws more attention to other parameters, such as rhythm and inflection... In the sixteenth century, a series of common sizes developed among European typographers, and the series survived with little change and few additions for 400 years... This is the typographic equivalent of the diatonic scale."

Robert Bringhurst - The Elements of Typographic Style

Inch 72pt = 96px

Five line pica 60pt = 80px

Canon 48pt = 62px

Double great primer 36pt = 48px

Double pica 24pt = 32px

Double small pica 21pt = 28px

Great primer 18pt = 24px

Columbian 16pt = 21px

English 14pt = 19px

Pica 12pt = 16px

Not suggested for web use

Small-pica 11pt = 15px

Long-primer 10pt = 13px

bourgeois 9pt = 12px

petit 8pt = 11px

minion 7pt = 9px

nonpareille 6pt = 8px