Sentence Counter
Sentences counted live, with the average words per sentence alongside — the single fastest diagnostic for whether your writing flows or plods.
Reading the average
The average is a rhythm gauge, not a grade. Fifteen to twenty words per sentence suits most general writing; journalism often runs shorter, legal and academic prose longer. What the average hides is variance — strong writing mixes short punches with longer, flowing sentences — so treat a high average as an invitation to find the three-clause monsters and split them, not as a command to make everything terse.
Worked example: where the count can surprise you
Paste "Dr. Smith arrived at 9 a.m. She left early." and the counter reports 3 sentences where a human reader sees 2. Walking through it explains the whole heuristic. A sentence ends at a run of ending punctuation followed by a space or the end of the text — so the period after "Dr." (period, then space) registers as a break, which is the false extra. The first period inside "a.m." does not break anything, because it is followed by a letter, not a space; the second one does, but that break coincides with the real sentence end, so no harm done. The same followed-by-a-letter rule is why decimals are safe: "Pi is 3.14 to two decimal places." counts as exactly 1 sentence. Ellipses and mixed punctuation work as expected — "Wait… what happened? Tell me everything!" is 3 sentences, and a run like "?!" counts once, not twice.
In practice the error is small and one-directional: abbreviations such as "Dr.", "e.g.", or "U.S." each add at most one phantom sentence, so prose heavy with them over-counts slightly and never under-counts. For a quick correction, subtract one per mid-sentence abbreviation. The average words-per-sentence figure is more robust than the raw count for judging style — a phantom break or two barely moves it on any text longer than a paragraph — which is why it sits beside the count above.
Frequently asked questions
How does it decide where a sentence ends?
At runs of ending punctuation — periods, question marks, exclamation points, ellipses — followed by a space or the end of the text. Abbreviations like "Mr." or "e.g." therefore register as sentence breaks, a known limitation shared by most counters and documented on our methodology page.
What is a good average sentence length?
Plain-language guidance clusters around 15–20 words for general audiences, with variety mattering as much as the average — a wall of same-length sentences reads monotone. Averages above ~25 usually signal sentences worth splitting.
Do headings and fragments count?
A heading or fragment without ending punctuation counts as a sentence only if it is followed by the end of the text (it contains words, so the final segment registers). For prose analysis, paste body text rather than heading-heavy outlines.
Why does sentence count matter for readability?
Words-per-sentence is half of the classic Flesch readability formulas — long sentences are the fastest way to make text harder to read. For full readability scoring, our sister site WordCounterPro.ai has a dedicated readability checker.
Counting happens locally in your browser — nothing you type is transmitted or stored. See the methodology page for the exact sentence-splitting rules.