Updated · Built and checked by the PlinzoTools team, formulas tested against published sources
Calculate the average number of words per sentence in any text.
Sentence length is one of the simplest, most direct readability signals -- longer average sentences generally mean harder-to-follow text. This tool calculates it directly.
Paste your text. Word count, sentence count, and the average appear instantly.
Average words per sentence = total words / total sentences
The calculator counts words as runs of letters, digits, and apostrophes, so "don't" is one word while a hyphenated term such as "well-known" is counted as two. Sentences are found by splitting the text wherever a period, exclamation mark, or question mark is followed by whitespace or the end of the text. Anything left between those breaks is one sentence, so a heading or a bullet with no closing punctuation gets merged with the line that follows it. Keep this in mind when pasting formatted content.
Consider this hypothetical passage: "Our new plan starts Monday. Please read the attached schedule before the meeting, and bring questions about shifts, deadlines, or equipment. Thanks!" The first sentence has 5 words, the second has 16, and the third has 1. That is 22 words across 3 sentences, so the average is 22 / 3, roughly 7.3 words per sentence.
Average = 22 words / 3 sentences = 7.3 words per sentence
The average alone hides the spread. Here one sentence is more than twice as long as the other two combined. If you want smoother reading, look at the outlier rather than the mean.
Average sentence length works best as a comparison against your own writing goals rather than an absolute grade. Paste a section, note the average, revise the longest sentences, and paste again to see the change. A useful habit is to test the opening paragraph of an article separately, since readers decide there whether to continue.
If the average is higher than you want, look for sentences joined by "and", "which", or "because" that could stand as two sentences. Move background details into their own sentence, replace long phrases with a single word, and cut openers such as "it is important to note that". Avoid the opposite mistake of chopping everything into fragments, since that damages flow and can make the text feel abrupt.
Sentence length is only one ingredient of readability. Word length matters as well, which is why formal readability scores such as Flesch Reading Ease also look at syllables. Use the Readability Score Calculator alongside this tool when you need a fuller picture, and remember that no number replaces reading your text aloud and hearing where it stumbles.
Most style guides suggest keeping average sentence length under 20 words for general web content, though this varies by audience and content type.
Numbers count as words because digits are treated like letters. Standalone symbols such as dashes or ampersands are ignored and do not add to the word count.
List items usually lack ending punctuation, so several items are merged into one long sentence. Add periods to items, or analyze only the flowing prose.
Yes. Periods, exclamation marks, and question marks all end a sentence when followed by a space or the end of the text.
No. Very low averages can signal choppy writing. The aim is clarity for your audience, with a mix of short and longer sentences.
Reference: Google Search Central