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Sentence Length: How Long Should a Sentence Be?

Counting sentences sounds trivial until you try it on real writing. Dr. Rao, e.g. and J. K. Rowling all contain full stops that do not end anything, and a counter that splits at every dot will report nonsense. Once the count is right, the more useful number is length: how many words each sentence carries, and how many run long enough to lose a reader. This guide covers how sentence counting actually works, what average and median length tell you, and how to edit a paragraph that is hard to follow.

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Why counting sentences is harder than it looks

Full stops lie.

The simple rule is that a sentence ends at a full stop, question mark or exclamation mark followed by a space. That rule works for most text and fails in predictable places. Titles like Mr., Mrs. and Dr. are followed by a space and a capital letter, which looks exactly like a new sentence. So do initials in a name, abbreviations like e.g. and i.e., and times written as 5 p.m.

A careful counter keeps a list of common abbreviations and treats a full stop after one of them, or after a single capital letter, as part of the sentence. The Sentence Counter does this by default, so Dr. Smith met J. K. Rowling at 5 p.m. counts as one sentence, not five. The trade-off is that a sentence which genuinely ends on an abbreviation can be merged with the next one, which is why the option can be switched off.

Line breaks are the other judgment call. In prose, a single line break inside a paragraph is usually just wrapping. In a bullet list or a set of headings, each line is its own unit even without a full stop. Tick Each line is a sentence for that kind of text.

What average sentence length tells you

One number, read carefully.

Average sentence length is total words divided by total sentences. Plain language guides commonly suggest an average of around 15 to 20 words for general readers, and the readability formulas used in word processors lean heavily on this figure. Longer averages are normal in academic and legal writing, where precision matters more than speed.

The average has a weakness: one very long sentence pulls it up. A paragraph with four 8 word sentences and one 60 word sentence averages 18.4 words, which sounds comfortable, yet the reader still has to fight through the 60 word monster. That is why the Sentence Counter also shows the median, the middle length when all sentences are sorted, plus the longest and shortest sentence. When the average is well above the median, a few sentences are doing the damage.

Reading the sentence length spread

Rhythm, not uniformity.

Good writing mixes lengths. Short sentences land a point. Longer ones carry an explanation with its conditions attached. A text where every sentence is 12 words long reads like a list of instructions, and a text where every sentence is 30 words long reads like a contract.

The length spread groups sentences into bands of 1 to 10, 11 to 20, 21 to 30 and 31 or more words. For most web and business writing, expect the bulk of sentences in the first two bands, a handful in the third and very few in the last. If the 31+ band is busy, that is where editing time pays off first.

A worked example: fixing one long sentence

Before and after.

Take this sentence from a project update: The middle section, however, runs on for far too long because every point is followed by another point, then an example, then a caveat, and by the time the reader reaches the end of the sentence they have forgotten how it started. It is 42 words long, and the Sentence Counter flags it against a 25 word limit.

Split it where the ideas change: The middle section runs on for far too long. Every point is followed by another point, then an example, then a caveat. By the end, the reader has forgotten how it started. That gives three sentences of 9, 13 and 10 words, and nothing was lost. The however disappeared because the new rhythm makes the contrast obvious.

Run the edited paragraph through the counter again and the longest sentence drops from 42 to 13 words, while the average moves closer to the median. That is the pattern to aim for: fewer outliers, not shorter sentences everywhere.

Common sentence counting mistakes

Where totals drift.

Most disagreements about a sentence count come from a handful of causes.

Counting headings as sentences. A heading without a full stop is usually merged with the paragraph after it unless each line is treated as a sentence.
Ellipses in the middle of a thought. Three dots followed by a space end a sentence under the standard rule, so trailing thoughts can add to the count.
Quotes and brackets. A sentence that ends inside a closing quote or bracket still counts once; the closing mark stays with the sentence.
Numbered lists copied from a document. Items like 1. Introduction look like sentence endings, so check the list view for tiny sentences.
Comparing with Microsoft Word. Word's Word Count window does not show sentences at all, so a published figure may come from a different tool with different rules.

Using the Sentence Counter in your editing routine

Count, sort, fix.

Paste the draft or open the .docx, set Long sentence limit to the figure your style guide uses, and read the summary. Then sort Every sentence by Longest first and work down the list until nothing is flagged, or tick Only long sentences to hide the rest. The question and exclamation counts are a quick tone check too: a sales page with no questions at all may not be talking to the reader.

For totals beyond sentences, the Word Counter adds readability scores and keyword density, and the Reading Time Calculator shows whether the tightened draft is also quicker to read. Copy one per line exports each sentence on its own line, which makes a handy checklist for a line edit in another document.