Paste or type. Sentences, words per sentence, and average length update instantly, in your browser.
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A sentence counter tells you how many sentences are in a piece of text, how long they are on average, and where the longest and shortest ones fall. This tool counts as you type, reports words per sentence, and flags writing that leans on run-on sentences. Everything runs in your browser. Nothing is uploaded.
The tool counts a sentence at each run of terminal punctuation, a period, question mark, or exclamation point, that is followed by a space or the end of the text. That single rule handles the large majority of normal prose. It then divides the total word count by the sentence count to give you the average sentence length, the single most useful number for judging how readable the text is.
Average sentence length is the strongest lever you have over readability. Long sentences force a reader to hold more in mind before reaching the point, and past about 25 words comprehension starts to drop. A healthy average for general web and business writing is 15 to 20 words per sentence, with variety: a mix of short and medium sentences reads better than a string of identical ones. If your average climbs above 25, the fix is almost always to split the longest sentences in two.
Editing for clarity. Spot the run-on sentences pulling your average up, then split them. The longest-sentence readout points you straight at the worst offender.
Academic and report writing. Many style guides cap average sentence length. The counter confirms you are inside the limit before you submit.
Meta descriptions and ad copy. When you need exactly one or two tight sentences in a fixed space, the counter keeps you honest.
ESL and learning. Counting sentences and seeing their length helps learners build a feel for natural sentence rhythm.
Summaries and abstracts. When a brief asks for "three sentences," the counter is the fastest way to hit the count exactly.
Every readability formula, Flesch Reading Ease, Flesch-Kincaid, Gunning Fog, and SMOG, uses average sentence length as a core input. Shorter sentences raise the reading-ease score and lower the grade level. That is why the sentence counter pairs naturally with a readability checker: this tool shows you the sentence-length number directly, and the readability tool shows you what that number does to the grade. A word counter covers overall length, and a syllable counter covers the other half of the readability equation, word length.
No simple rule is perfect. Abbreviations like "Dr." or "U.S." contain periods that are not sentence ends, and the counter may read them as breaks. Decimal numbers, ellipses, and URLs can do the same. For ordinary prose the count is accurate; in text dense with abbreviations or numbers, expect the sentence count to run slightly high. The word count and character count are unaffected by these edge cases and stay exact.
Type or paste text and the counts update on every keystroke. Sentences are detected by terminal punctuation, words are split on whitespace, and paragraphs are split on blank lines. The tool also reports the longest and shortest sentence in words, the character total, and the average characters per sentence. Everything is computed locally, so your text never leaves the page. You can confirm that in your browser network panel.
It counts a sentence wherever a period, question mark, or exclamation point is followed by a space or the end of the text. That rule matches normal prose closely. Text packed with abbreviations or decimal numbers can push the count slightly high, because those periods look like sentence ends.
For general web and business writing, 15 to 20 words per sentence reads comfortably, with a mix of short and medium sentences. Above about 25 words, comprehension drops and the text starts to feel like work. The fix is to split the longest sentences in two.
Abbreviations such as "Dr." and "U.S.", decimal numbers, ellipses, and URLs all contain periods that are not sentence ends, so a simple counter reads them as breaks. In ordinary prose this is rare; in text dense with those forms, expect a slightly inflated count.
Yes. Paragraphs are counted by blank lines between blocks of text. Along with sentences and words, that gives you a full picture of structure, useful for checking essay and article formatting at a glance.
Yes. When a brief asks for a set number of sentences, such as a three-sentence summary or a two-sentence meta description, type into the box and watch the sentence count to land on the target exactly.
No. The counting runs entirely in your browser. Nothing is sent to a server, logged, or stored. You can verify by watching your browser network tab stay empty as you type.