Type Anatomy & Classification · Page 2 of 8

Where do letters sit?

Every letter in a typeface lines up on the same invisible guidelines.

Type designers draw every letter of a typeface to line up on a set of invisible horizontal guidelines. Learn them first, because almost every other anatomy term is described by where it sits on these lines.

The letters H, x, d, p and g with five guidelines: the ascender line at the top of the d, the cap height at the top of the H, the x-height at the top of the x, the baseline where the letters sit, and the descender line at the bottom of the p. Ascender line Cap height x-height Baseline Descender line
Five guidelines, shown in Libre Caslon Text. The letters were drawn from the font’s real outlines, so every line is exact.

The five guidelines

  1. Baseline

    The imaginary line the text rests on. Round letters like o and g dip just below it so they look like they sit on it.

  2. x-height

    The height of the lowercase letters without ascenders or descenders, measured by the height of a lowercase x.

  3. Cap height

    The height of the uppercase letters, measured from the baseline to the top of a flat capital like H.

  4. Ascender

    The part of a lowercase letter that rises above the x-height, as in b, d, h, k and l. In many typefaces the ascenders are taller than the capitals.

  5. Descender

    The part of a lowercase letter that dips below the baseline, as in g, j, p, q and y.

Why x-height matters

Two typefaces set at the same point size can look very different in size. The difference is the x-height: a larger x-height makes a typeface look bigger and easier to read on screens and at small sizes.

Small x-heightHandglovesEB Garamond at 40 px
Large x-heightHandglovesSource Sans 3 at 40 px

Space between letters and lines

Three spacing terms describe the room around the letters. You’ll adjust all three in InDesign, Illustrator and Figma.

Kerning

Adjusting the space between two individual letters. Some pairs, like AV, To and Ya, leave awkward gaps unless they’re kerned.

AVATAR TowerNot kerned
AVATAR TowerKerned

Tracking

Adjusting the overall letterspacing of a whole word, line or paragraph.

typographyTight
typographyNormal
typographyLoose

Leading

The vertical space from the baseline of one line to the baseline of the next. Also called line spacing. It rhymes with “wedding”: printers once added strips of lead between lines of metal type.

Tight leading makes lines crowd each other, so the eye slips to the wrong line.

Comfortable leading gives each line room, so the eye finds the next one easily.

Point size

Type size is measured in points (72 points = 1 inch). The point size measures the whole body the letters were designed in, not any one letter, which is why x-heights can differ so much at the same size.

© Created by Sara Rosenstock, Marietta College Graphic Design.