Average Sentence Length Calculator

The average sentence length calculator measures how long the sentences in your text are and shows the average words per sentence. It divides the total number of words by the number of sentences, so you can see the average in one step.

The results also include the median, the longest and shortest sentences, and how sentences are spread across length groups. Paragraph averages show average paragraph length in both sentences and words, so you can compare sentence and paragraph size in the same text.

The tool runs in your browser. It is free, with no sign-up or account. It measures sentence length only and does not grade or correct your writing.

How to use the Average Sentence Length Calculator

1. Type or paste your text into the Text box. Leave a blank line between paragraphs.
2. If your text is a list, tick Count each line as a sentence.
3. Read Average words per sentence, the large number in the results.
4. Compare Median sentence length (words) with the average. Check Longest sentence (words) and Shortest sentence (words) for the range.
5. Confirm Sentences and Words match what you expect from your text.
6. Read Average sentences per paragraph and Average words per paragraph for paragraph length.
7. Open the table Sentences by length (this tool’s own groups, in words) and the bar chart to see each group’s count and share.

To try the tool first, use the presets Easy sample, Medium sample, Hard sample or A list of lines. The page opens with the Medium sample and Hard sample loaded together, which gives 7 sentences, 80 words and an average of 11.4.

You can paste up to 200,000 characters. Nothing you enter is sent anywhere. Use Copy result to copy the numbers as text, Copy link to copy a web address that reopens the tool with your settings, and Print / save as PDF to keep a record. Reset returns the tool to its starting sample. A very long pasted text is left out of the copied link.

How do I calculate average sentence length?

Divide the number of words by the number of sentences. The result is the average sentence length in words, shown with one decimal place.

For example, “The cat sat. The dog ran home!” has 7 words and 2 sentences, so 7 / 2 = 3.5. The tool counts sentences the same way as the sentence counter page, so abbreviations, decimals and initials do not end a sentence.

What is a good average sentence length?

The tool does not set a target, so no average is right or wrong on its own. The US federal plain language guide at digital.gov says short sentences should each express one idea, but it gives no word count.

Readability formulas such as the Flesch formulas use average words per sentence as one input. They measure sentence and word length only. They cannot judge meaning, correctness or whether a text suits a reader.

What is average paragraph length?

Average paragraph length is the average number of sentences and the average number of words per paragraph. A paragraph is a block of text between blank lines, whether or not the list checkbox is ticked.

The tool divides sentences by paragraphs and words by paragraphs. In the text “One two. Three four. Five six.” followed by a blank line and “Seven eight nine ten eleven twelve? Here”, there are 5 sentences and 13 words across 2 paragraphs. That gives 2.5 sentences and 6.5 words per paragraph.

The federal guide offers this advice: “Writing experts recommend paragraphs of no more than 150 words in three to eight sentences” and “Paragraphs should never be longer than 250 words.” Treat these as guidance, not a pass or fail test.

Mean or median?

The tool shows both. The average (mean) is total words divided by sentences, so one very long sentence pulls it up. The median is the middle sentence length after sorting. With an even number of sentences, it is the mean of the two middle values, shown like 6.5.

The median ignores how long the few longest sentences are. Sentences of 10, 11, 20, 21 and 31 words give an average of 18.6 (93 / 5) and a median of 20. A long sentence raises the average more than a short one lowers it, so when the two numbers differ, check the group table.

How many sentences are over 20 words?

Add the counts in the 21-30 and 31+ rows of the table. These groups are this tool’s own grouping, not a published scale.

In the example above, the sentences of 21 and 31 words are over 20 words. The 21-30 row shows 1 sentence (20%) and the 31+ row shows 1 sentence (20%), so 2 sentences in total, or 40%.

How do I count a list as sentences?

Tick “Count each line as a sentence”. Each line then counts as one sentence.

For the list “Buy milk / Call the dentist / Write the report / Walk the dog” with the box ticked, the tool counts 4 sentences of 2, 3, 3 and 3 words. The average is 2.8 and the median is 3.

Sources (checked 2026-10-15): Federal plain language guidelines (digital.gov).

Worked examples

Calculated by the tool above; open it with the same values to see each step.

Frequently asked questions

Is my text uploaded or stored?

No. Everything runs in your browser, and the text you paste is never uploaded or stored by the site.

Does this tool tell me whether my writing is good?

No. Readability formulas only measure sentence length and word or syllable length. Syllable counts come from a dictionary where the word is listed and a rule-based estimate otherwise, so scores are estimates.

Why does the tool show a short text note?

With fewer than 3 sentences, the page shows “Very short text: with fewer than 3 sentences the average says little.” Two or three sentences can give an average that changes a lot if you edit one of them.

How does the tool find where sentences end?

It splits sentences the same way as the sentence counter page. Abbreviations, decimals and initials do not end a sentence. The tool accepts up to 200,000 characters.

Can I share or print my result?

Copy result copies the numbers as text, Copy link copies a web address that reopens the tool with your settings, and Print / save as PDF opens your browser’s print dialog. A very long pasted text is left out of the link.

What does the length table show?

It counts the sentences in four groups of 1-10, 11-20, 21-30 and 31 or more words, with each group’s share of all sentences. The groups are this tool’s own and are not a published scale.

Related tools

• Sentence counter: use it when you only need the sentence total, with the same splitting rules.
• Syllable counter: use it to check syllables per word, the other input to the Flesch formulas.
• Readability checker: use it for a readability check of your text as a whole.
• Readability formulas compared: use it to see what each readability formula measures.
• Plain language examples and checker: use it to look at plain language examples and try the checker there.