Legible Isn't the Same as Readable

Legibility and readability get used as if they mean the same thing. They don't, and the difference explains why some websites pass every accessibility check and still feel tiring to read.

Legibility is about whether individual letters and words can be made out. Is the text big enough? Is there enough contrast against the background? Can you tell a lower-case l from a capital I? These questions have measurable answers, and the Web Content Accessibility Guidelines give clear thresholds, such as a contrast ratio of at least 4.5:1 for body text.

Readability is about how easy it is to take in a whole passage. It depends on line length, line spacing, paragraph structure, the rhythm of the layout and the words themselves. You can't measure it with a single tool, but you can feel it after three paragraphs.

Passing the checks isn't enough

We treat legibility as the floor. Every project meets the contrast and size requirements, because without them some readers can't use the site at all. But meeting them doesn't mean the job is done.

A paragraph that runs across the full width of a large monitor can be perfectly legible and still hard to read, because the eye struggles to find the start of the next line. Text set with tight line spacing passes contrast checks but feels cramped. A page of long, unbroken paragraphs is legible in every technical sense and still something most people will skim and leave.

Line length and spacing

Line length has the biggest effect. We aim for roughly 60 to 75 characters per line for body text. Shorter than that and the eye jumps too often; longer and it loses its place. On wide screens, that means constraining the text column rather than letting it stretch, even if the layout around it is wider.

Line height comes next. Body text usually needs a line height of around 1.5 to give each line room. Longer lines need a little more, and short lines in headings need less.

Paragraph spacing finishes the job. A clear gap between paragraphs gives readers natural pause points and makes the page look approachable before anyone reads a word.

Structure helps people read

Most people scan web pages before they decide to read them. Good subheadings let them see what's coming and jump to the part they need. Short paragraphs, each with one idea, are easier to follow than long ones covering three. Lists work well for steps or options, as long as they aren't used for everything.

These are writing decisions as much as design decisions, which is why our content writing and design work happen together rather than one after the other.

Words matter too

The most carefully set paragraph is still hard work if the sentences are long and full of jargon. Plain language, shorter sentences and familiar words make text readable for more people, including those reading in a second language or on a small screen while doing something else.

Contrast with comfort in mind

Contrast has an upper end too. Pure black text on a pure white background is very legible, but some readers find it harsh over long passages. A very dark grey on an off-white often reads more comfortably while still easily exceeding the minimum ratio. The aim is text that's easy to read for twenty minutes, not just for a glance.

Testing by reading

Our final check is the simplest. We read the page, all of it, on a phone and on a laptop. If we find ourselves skimming our own copy or losing our place, something needs fixing. Tools can tell you whether text passes. Only reading it tells you whether it works.

If your content is accurate but people aren't getting through it, the problem might be readability rather than the words. Get in touch and we'll take a look.