TontonTools

Sentence Counter

Count sentences in any text instantly — plus words and averages.

100% Free No signup Privacy-friendly Text Tools
Updated Sep 2026
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How to use Sentence Counter

  1. Paste or type your text into the box — anything from one paragraph to a full essay.
  2. Read the live counts: sentences are tallied instantly as you write or edit.
  3. Watch the average — if words-per-sentence creeps past ~25, look for sentences to split.
  4. Edit in place and watch the numbers update until the text meets your target.

What is Sentence Counter?

A sentence counter tallies how many sentences a piece of text contains by detecting terminal punctuation — periods, question marks and exclamation points. Alongside the raw count, the interesting number is usually words per sentence: professional writing averages 15–20; past 25, readers start losing the thread.

Sentence count matters wherever length is judged in sentences rather than words: exam answers ("in 3–5 sentences"), abstracts and summaries with sentence caps, meta descriptions, and readability targets — every major readability formula, from Flesch to SMOG, is built on sentence length.

About the Sentence Counter

Paste or type your text and the sentence count updates live, with no button to press. It is the quick way to check an assignment's "answer in five sentences" constraint, to verify a summary stayed within its cap, or to diagnose why a paragraph feels exhausting — usually a 40-word sentence hiding in the middle.

Writers and editors use sentence counts to control rhythm: strings of same-length sentences read monotonously, and a passage averaging over 25 words per sentence almost always benefits from splitting. Teachers use it for grading constraints; SEO writers keep intro sentences tight for featured snippets.

Counting happens in your browser as you type — your text is never uploaded or stored.

Frequently Asked Questions

It splits on terminal punctuation — periods, question marks and exclamation points. Text without any terminal punctuation counts as one sentence.
15–20 words for general writing. News agencies aim under 20; plain-language guidelines suggest varying between short (5–10) and medium sentences, keeping the average below 20.
A period after an abbreviation can register as a sentence end — an inherent limit of punctuation-based counting shared by most tools. For typical prose the count stays accurate within a sentence or two.
Convention says 3–5, but it is a style choice: journalism runs 1–2 sentence paragraphs for pace, academic writing 5–8. Web writing favors short paragraphs because walls of text lose readers.
Sentence length is one of the two inputs (with word complexity) in nearly every formula — Flesch, Kincaid, SMOG, ARI. Shortening sentences is the fastest lever for improving a readability score.

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