Nobody finishes a post they couldn't comfortably read. Before your ideas get judged, your typography already voted — silently, in the first ten seconds, when the reader's eye decided whether this page felt like work. The encouraging news: readable typography is not a designer skill. It's about a dozen numbers, most of which have well-established correct answers for long-form text. Here they are.
Measure first: the 45–75 character line#
The single most important number in reading comfort is line length — "measure" in typographic terms. Decades of readability research converge on 45–75 characters per line, with ~66 the classic sweet spot for body text.
- Too long (90+ characters): eyes lose the return path to the next line; readers skip lines and fatigue early.
- Too short (under 40): the eye bounces constantly; rhythm shatters.
On the web this is controlled by constraining content width, not by shrinking fonts. For a typical 16–18px body size, that means a content column around 620–720 pixels — which feels shockingly narrow to anyone who grew up on full-screen Word documents, until they notice how every serious publication does exactly the same. If your theme stretches text edge to edge on a desktop monitor, fixing that one value improves every post at once.
Size and leading: err generous#
Body text on screens wants to be bigger than print instinct suggests:
- 16px is the floor, 18–20px is the sweet spot for long-form on modern screens. If your audience skews older, lean up.
- Line height between 1.5 and 1.7 for body copy. Dense leading (1.2) makes multi-line paragraphs merge into gray blocks; airy leading (1.9+) makes paragraphs fall apart into disconnected lines.
- Paragraph spacing should clearly exceed line spacing so paragraph boundaries are visible from across the room — web readers skim by jumping between paragraph starts.
The mobile multiplier: all of these matter twice as much on a phone, where reading happens in buses and queues. Check posts on an actual small screen before shipping a theme; desktop-only review is how bad mobile typography ships.
Hierarchy: three sizes and discipline#
Readers navigating a page use headings as handholds, which means hierarchy must be visible at squint-distance:
- Post title: largest thing on the page, no competition.
- Section headings: unmistakably larger/bolder than body — roughly 1.3–1.6× body size. This doubles as structure for assistive tech (heading order matters beyond looks).
- Body: the comfortable baseline above.
- Everything else — captions, meta info, footnotes — smaller and quieter than body, consistently.
The common failure isn't lacking styles; it's too many competing ones. Six font sizes, four weights, two typefaces per element — each addition asks readers to re-orient. Two typefaces maximum (one for headings, one for body — or one family doing both jobs), three or four sizes total, used religiously.
The details that quietly signal quality#
Small things, disproportionate effect:
- Line length under 75 chars, checked on real devices.
- Bold used as seasoning, not salt. If twenty phrases per post are bold, none are. Bold marks the handful of sentences a skimmer must catch.
- Lists earn their markup. Bullets for genuinely parallel items, numbered only where sequence matters. Lists fragment flow, so prose should win ties.
- Links styled beyond color alone — underline them; a meaningful share of readers can't rely on hue differences (see the accessibility case).
- Sentence-case headlines are friendlier and easier to scan than Title Case Walls; pick one convention and enforce it sitewide.
A five-minute audit for any blog#
Open your longest recent post and check:
- Content column ≤ ~720px on desktop?
- Body ≥ 16px with ≥1.5 line height?
- Can you identify sections while squinting at a blurred screenshot?
- Any paragraph longer than ~6 lines on a phone?
- Do links look like links without color vision?
Five yeses means typography has stopped being an obstacle — readers now judge only your ideas, which is where you want the argument happening. Typography done right is invisible; its absence is what readers remember.
Related: Core Web Vitals covers the speed half of reading experience, and writing titles covers the moment before typography gets its chance.
