How one finds out the alphabet length or individual character width of a typeface?

Question

I would like a quick way to determine the column width necessary to create the optimal 65 characters per line rule. Glyph width differs between typefaces, so this article suggested:

The alphabet length is determined by the width of the lowercase a through z, historically measured in points. This measurement varies depending upon the typestyle and point size being used. Therefore, varying the font and/or point size will affect the optimum column width.

I have googled "alphabet length of ___ font" and got nothing.

Answer 1

The article doesn't give you any formula or action to take with the alphabet length once you have it, it only states that is affects the optimum column width but suggests determining column width by word or character numbers. So, if the only reason you want to measure your alphabet width is because of that quote in the article, there's no need.

If you do want to measure the alphabet length, the quote tells you exactly how to do it in the first sentence!

The alphabet length is determined by the width of the lowercase a through z, historically measured in points. This measurement varies depending upon the typestyle and point size being used. Therefore, varying the font and/or point size will affect the optimum column width.

Type out lowercase a-z and measure the width. Done.

It depends what you're doing but it's often useful to compare alphabet lengths relative to each other, but not taking literal measurements.

I don't suggest setting your column width based on a set formula (e.g. exact multiple of character widths). Line length is only one factor in readability. Typefaces used, leading, margins, number of columns, context etc. all impact on readability.

Answer 2

Here's how

The line length of the full alphabet in lower-case (miniscules) measured in ems is the easiest, fastest and most accurate way to compare fonts.

In practice, about 30 ems has become the "best-practice" for line length. That works out to roughly two-and-a-half average-sized "alphabets." That works out to about 65 characters…

on average, that is. We would refer to that condition as regular or medium set type.

When that length is exceeded, we say that the face is extended—wider than normal. Those are best-suited to compose wide-measure lines and letter-spaced text.

It's easier to read.

When that line length is less, we say that the face is condensed—narrower than normal and is best suited to compose narrow column of text to avoid over hyphenation and awkward word breaks.

It's easier to read.

TIP: for quick calculation and evaluation of unfamiliar faces: Set 12pt sized alphabets so that one pica is equal to one em. Then, you can use a normal type stick to read the pica-length directly in "ems."

It's easier to read.

NOTE: An em, you'll recall, is the point size (full vertical height of the typeface) when used horizontally. Thus 1 em of an 8 point typeface is 8 points. 1 em of a 72 point typeface is 72 points.