Typography for people who are not designers

Most of what makes text readable comes down to a handful of decisions. You do not need taste to get them right — you need to know which five they are.

1. Measure before typeface

Line length does more for readability than font choice, and it is the decision most often left to whatever the container happens to be. Aim for 60–75 characters. Below 45 the eye jumps too often; above 90 it loses the return.

2. Line height scales with measure

A longer line needs more leading, because the return journey is longer and the eye needs a bigger target. A 45-character line is comfortable at 1.4; a 75-character line usually wants 1.6 or more.

3. Size is a function of distance

The right body size depends on how far the reader sits from the screen, which you cannot know — so err large. Sixteen pixels is a floor, not a target.

4. Contrast is measurable

You do not have to argue about whether grey text is too light. WCAG AA asks for 4.5:1 for body text, and any browser's dev tools will tell you the number.

5. Hierarchy needs fewer levels than you think

Three levels of heading is usually enough for an article. If you need four, the article probably wants splitting.