Sentence counter
Count sentences, paragraphs and average sentence length. Results update as you type.
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About sentence length and readability
Sentence length is one of the strongest predictors of how easy text is to read — it sits at the heart of every major readability formula, from Flesch–Kincaid to the Gunning Fog Index. English prose has also been getting steadily shorter: scholars who studied historical writing found average sentences of 40 to 60 words in Elizabethan times, around 30 in the Victorian era, and closer to 15 to 20 in modern journalism. Counting sentences, measuring their average length and seeing their distribution tells you more about how your writing feels to a reader than a word count alone ever can.
How many words are in a sentence
There is no rule, but there are well-established norms. Modern English prose averages 15 to 20 words per sentence, and that is the range plain-language guidance — including the US government's own standards — recommends for anything written for a general audience. Below about 10 the writing starts to feel clipped; above 25 the reader has to hold too much in mind before reaching the verb. Academic and legal writing routinely averages 25 to 30 words, which is a large part of why it reads as heavy going.
The average matters less than the spread, though. Text where every sentence is 18 words long is monotonous even at a perfect average, while prose that mixes a 30-word sentence with a 4-word one has rhythm. This is why the counter reports the distribution alongside the average words per sentence, plus your longest and shortest sentence — the average tells you whether you are in range, and the distribution tells you whether you are varying.
| Average words per sentence | Reads as | Typical of |
|---|---|---|
| Under 10 | Clipped, staccato | Children's books, advertising copy |
| 11–15 | Brisk and clear | Popular journalism, plain-language writing |
| 16–20 | Comfortable | Most web content, general non-fiction |
| 21–25 | Demanding | Broadsheet features, trade publications |
| Over 25 | Heavy going | Academic papers, legal and technical writing |
Sentence length distribution
The distribution chart shows how your sentences break down by length category. Short sentences of 1 to 10 words are punchy and easy to read but too many can make text feel choppy. Medium sentences of 11 to 20 words carry most of the content in well-written prose and are the ideal target range. Long sentences of 21 to 30 words add complexity and nuance but should be used sparingly. Very long sentences of 31 or more words are difficult to follow and should almost always be broken into shorter ones.
Good writing varies sentence length to create rhythm. A mix of short, medium, and occasional long sentences reads more naturally than text where every sentence is the same length. If your distribution shows mostly very long sentences, the reading level checker will likely show a high difficulty score — break them up to improve both readability and comprehension.
Sentence count is one of several length measures worth reading together. The word counter reports words, characters and reading time; words to pages turns the total into a page estimate for an assignment specified in pages; and the word frequency counter catches the words you repeat once the structure is sound.
Frequently asked questions
How does the sentence counter detect sentences?
It scans for ending punctuation — periods, exclamation marks and question marks — while intelligently skipping the cases that fool naive counters. Abbreviations like Mr., Dr. and U.S.A. are recognised and not treated as sentence endings, decimal numbers like 3.14 are handled correctly, and an ellipsis counts as a single ending rather than three periods. The result is an accurate count even in complex professional text, updated live as you type.
What is the ideal sentence length for readability?
Aim for an average of 15 to 20 words for general web content — the range recommended by most readability guidelines, including the US government's plain-language standards, which cap sentences at 20 words. For context, Hemingway's famously terse style averaged around 10 words, while academic writing often runs 25 to 30. Anything past 30 words is hard to follow on first read, and the average matters less than variation: mixing short, medium and occasional long sentences is what gives prose its rhythm.
How many sentences should a paragraph have?
For screens, two to four sentences per paragraph works best. Long paragraphs of six or more sentences form dense walls of text that are especially punishing on mobile, where a single paragraph can fill the entire viewport. Short paragraphs create white space that makes a page feel approachable and lets readers scan for the point they need. Print tolerates longer paragraphs; the web rewards shorter ones.
What is the difference between a sentence counter and a paragraph counter?
A sentence counter counts units of thought ending in terminal punctuation; a paragraph counter counts blocks of text separated by blank lines. This tool reports both, plus the average sentences per paragraph — the structural metric editors care about most, because it reveals whether long text is actually well-organised or just long. Word and character counts round out the picture, but sentence-level structure is what distinguishes readable writing from dense writing.
Can I count sentences in multiple paragraphs at once?
Yes. Paste an entire essay, article or chapter and the counter processes all of it — there is no length limit that matters in practice. You get the total sentence count across the whole text, the paragraph count, and the per-paragraph averages, so you can spot outliers like a single paragraph carrying ten sentences while the rest carry three.