A blogger checks a new post on a phone and finds that a 220-word paragraph fills the whole screen with grey text and no place to rest. Nothing is wrong with the writing. The trouble is paragraph length and shape, and both are easy to fix. This guide explains what official plain-language and accessibility guidance says about paragraph length, how people actually read on screens, and how to edit a block of text into paragraphs that breathe.
Paragraph length: what the guidance says
The US government’s plain-language guide, Clear and short, gives numbers. It says writing experts recommend paragraphs of no more than 150 words in three to eight sentences, and that paragraphs should never be longer than 250 words. It also says there’s nothing wrong with an occasional one-sentence paragraph, and that each paragraph or section should be limited to one topic and open with a topic sentence that captures its essence.
Those are limits for plain-language government text, which is read by people who often need to act on it. A blog post can be looser. But the shape is useful: a topic sentence, a handful of supporting sentences, then a break.
Example: at roughly 6 characters per word including spaces and a narrow phone column of about 40 characters per line, a 150-word paragraph runs to around 22 lines. A 220-word paragraph runs to more than 30. These figures are an estimate, since real columns vary with font size and screen width, but they show why a paragraph that looks modest on a desktop can fill a phone screen.
How people read on screens
Nielsen Norman Group’s classic article, How Users Read on the Web, reports that 79 percent of its test users always scanned any new page they came across, and only about one in six read word for word. Scanning readers use the first words of a paragraph to decide whether to continue.
The same article recommends several tactics that apply directly to paragraph writing:
- Keep one idea per paragraph. Readers skip any additional ideas that the first few words don’t catch.
- Lead with the conclusion, in the style the article calls the inverted pyramid.
- Use meaningful sub-headings rather than clever ones.
- Use bulleted lists to present related items.
- Highlight keywords with links, typeface changes or colour.
It also advises writing half the word count or less compared with conventional writing. That’s a target for web copy, and not every article should be halved, but it’s a useful reminder that every sentence in a paragraph has to earn its place.
A rough guide to paragraph shapes
The table below is practical advice built on the plain-language limits above. Treat the sentence counts as starting points.
| Paragraph job | Typical length | Opening move | Use it when |
|---|---|---|---|
| Landing a point | 1 sentence | State the point plainly | You want a single claim to stand alone |
| Explaining | 3 to 5 sentences | Topic sentence, then reason or example | Most of the article |
| Walking through an example | 4 to 6 sentences | Label it: Example | A worked case needs several details |
| Warning or caveat | 2 to 3 sentences | Say what to watch for first | Safety, cost or accuracy matters |
| Transition | 1 to 2 sentences | Link the last idea to the next | A section changes direction |
Splitting a wall of text: a worked example
Word count alone doesn’t tell you when to split. This invented paragraph is 108 words, well inside the 150-word guideline, yet it carries three separate ideas.
Before (108 words):
Our newsletter sign-up page has three jobs. First, it has to say what subscribers get, and the clearest way to do that is to name the format and the schedule, such as one short email every Friday with three links. Second, it has to ask for as little as possible, which in practice means an email address and nothing else, because every extra field gives a visitor another reason to leave. Third, it has to say what happens next, so the page should tell people to expect a confirmation email and explain how to unsubscribe, since visitors who know the exit is easy are more willing to enter.
After (three paragraphs of 36, 31 and 32 words):
Our newsletter sign-up page has three jobs. First, it has to say what subscribers get. The clearest way is to name the format and the schedule, such as one short email every Friday with three links.
Second, it has to ask for as little as possible. In practice that means an email address and nothing else, because every extra field gives a visitor another reason to leave.
Third, it has to say what happens next. Tell people to expect a confirmation email and explain how to unsubscribe. Visitors who know the exit is easy are more willing to enter.
The words are almost identical. What changed is that a scanning reader can now see the three jobs by looking at the first words of each paragraph.
A five-step edit for a block of text
- Underline the ideas. Mark each place where the paragraph changes subject.
- Split at every change. Each new idea gets its own paragraph.
- Move the point to the front. If the main claim is at the end, bring it to the first sentence.
- Break long sentences. GOV.UK’s A to Z style guide says to check any sentence over 25 words to see if it can be split.
- Vary the rhythm. Follow a long paragraph with a short one, and don’t let more than two one-sentence paragraphs run in a row.
Cutting a paragraph in two doesn’t dilute an idea. It gives a skimming reader a place to land.
Line length and spacing
Paragraph shape depends on layout as well as words. The W3C’s guidance on the Visual Presentation success criterion (WCAG 2.1, SC 1.4.8, Level AAA) sets out these targets for blocks of text: a width of no more than 80 characters, line spacing of at least space-and-a-half within paragraphs, paragraph spacing at least 1.5 times larger than the line spacing, and text that is not justified.
A separate requirement at the lower AA level, the W3C’s Text Spacing criterion (SC 1.4.12, Level AA), says that no content or functionality may be lost when a user sets line height to at least 1.5 times the font size, paragraph spacing to at least 2 times the font size, letter spacing to at least 0.12 times the font size and word spacing to at least 0.16 times the font size. In practice, that means a page should survive a reader increasing the spacing, so avoid fixed-height boxes that clip text.
If your theme packs text tightly, check line height and the gap between paragraphs before rewriting anything. White space is free.
Headings, lists and bold
Subheadings work as signposts when they say something: Why most outlines fail tells a scanner more than The problem. Lists suit steps, options and parallel items, but ideas that depend on one another read better as prose. Bold is a signal, so reserve it for the term or warning a reader must not miss. If every second phrase is bold, nothing stands out.
Checklist before you publish
- Each paragraph covers a single idea
- The first sentence of each paragraph states its point
- No paragraph over 150 words, and none close to 250
- A few short paragraphs for emphasis, but not a long run of them
- Sentences over 25 words checked for splits
- Subheadings that say something specific
- Lists used for steps and parallel items only
- Line spacing and paragraph gaps checked on a phone
- Line width of 80 characters or fewer on desktop
- Read as a stranger would: can the topic be identified in a few seconds?
Common mistakes
The first is breaking every sentence onto its own line. A run of one-sentence paragraphs reads as choppy, and it removes the connections that make an argument. Keep related sentences together.
The second is judging the paragraph on a desktop monitor. Always preview on a phone before publishing.
The third is splitting by length alone. A 100-word paragraph with three ideas needs splitting; a 140-word paragraph with one idea may not.
The takeaway
Good paragraph length follows ideas, not word counts. Open each paragraph with its point, keep to one idea, stay well under 150 words, and check the spacing on a phone. The reader who scans will thank you by staying.
