Count sentences, words, paragraphs, and characters in real time — with average sentence length, readability level, and reading time. No signup required.
Also count words with the Word Counter or check readability with the Readability Checker.
Click the text area and paste any content — an essay, blog post, email, or product description.
Sentence count, word count, paragraph count, and character count all update in real time as you type.
Once you have 2+ sentences, the tool shows your average sentence length, estimated reading level, and reading time.
| Metric | Value | Assessment |
|---|---|---|
| Sentences | 12 | Good for a 200-word intro |
| Avg sentence length | 16.7 words | Standard (Grade 8–9) |
| Reading level | Grade 8–9 | Suitable for most web content |
| Reading time | ~1 min | Good intro length |
Average sentence length is a core input for readability formulas like Flesch-Kincaid. For SEO-friendly web content, aim for an average of 15–20 words per sentence. For a full readability check beyond sentence counting, try our Readability Checker.
A sentence counter — also called a sentence length analyzer or readability checker — measures text complexity beyond simple word count. Average sentence length is a core metric in Flesch-Kincaid, Gunning Fog, and other readability formulas used by SEO tools like Yoast and Hemingway.
Writers and content creators use sentence counters to ensure their writing stays accessible — long average sentence length is one of the primary reasons blog posts receive low Flesch readability scores. Academic writers use it to ensure their prose meets complexity requirements for their audience. SEO professionals use it alongside tools like our Keyword Density Checker to optimise content for both search engines and readers simultaneously.
Students writing academic papers use sentence counters to ensure their writing style matches the expected complexity for their course level — undergraduate essays typically target Grade 10–12 average sentence length, while high school writing targets Grade 8–9. The real-time paragraph count is also useful for checking whether an essay follows a required structure, such as a five-paragraph format with an introduction, three body paragraphs, and a conclusion.
For blog writers and content marketers, this tool works well as a quick pre-publish check. Paste a completed draft, verify the average sentence length sits between 15 and 20 words, then paste the same text into the Readability Checker to confirm the Flesch score before publishing. This two-step workflow catches most readability issues without needing a premium subscription to editing software.
Yoast SEO and Hemingway Editor recommend keeping most sentences under 20 words. Paste your content above to check your average instantly.