Automated Readability Index Calculator
Calculate ARI from English text with the Automated Readability Index selected as the headline. See the letters-and-digits count, word count, sentence count and substituted formula. Compare ARI with Flesch-Kincaid and Coleman-Liau below it.
- Grade
- not scored
- Ease
- not scored
- Words
- 0
- Sentences
- 0
The syllable count is the one estimate on this page. Correct a word here and both Flesch scores follow; Coleman-Liau and ARI never look at syllables.
Every score, with its working
The same text through four published formulas. They disagree, and the gap between the two that count syllables and the two that count letters shows how the choice of formula affects the estimate.
The counts every score is built from
Five of these numbers are what the formulas divide and multiply. They are on the page so a grade can be checked by hand rather than taken on trust.
| Count | This text | How it is counted |
|---|---|---|
| Words | 0 | Runs between spaces holding a letter or a digit, punctuation on the ends taken off. |
| Sentences | 0 | Splits on . ! ? and their CJK forms, skipping titles, initials and decimal points. Text with no full stop counts as one. |
| Syllables | 0 | Vowel groups in the word, with a silent final e removed, a silent ed and a silent es removed, and a word ending in a consonant plus le kept as its own syllable. A hyphenated word is counted a part at a time, and a word with no Latin letters, such as a number, counts as one. |
| Letters and digits | 0 | Letters and digits inside words. This is the letters of Coleman-Liau and the characters of ARI. |
| Characters | 0 | Everything typed, spaces and punctuation included. Not used by any of the four formulas. |
| Paragraphs | 0 | Blocks separated by a blank line. |
| Words a sentence | 0.00 | Words divided by sentences. Every one of the four formulas uses it. |
| Syllables a word | 0.000 | Syllables divided by words. Only Flesch-Kincaid and reading ease use it. |
| Letters a word | 0.000 | Letters and digits divided by words. Coleman-Liau and ARI use it instead of syllables. |
| Words of 3 syllables or more | 0 | Counted for reference. None of the four formulas uses it. |
What these numbers are, and what they are not
These four scores describe the text, not the person reading it. They are estimates worked out from counts, not a reading test and not a placement. A formula counts sentence length and word length, so it can be fooled: a list of short nonsense sentences scores as plain English, and one careful sentence with a long technical name in it scores as hard. Read the score as a pointer to the paragraph worth rewriting, then read the paragraph.
Common questions
- How is this score calculated?
- 4.71 × letters and digits per word + 0.5 × words per sentence − 21.43. The tool prints the text’s counts in the formula so you can follow the arithmetic.
- How should I interpret the score?
- The result estimates text complexity as a US school-grade level. It describes the writing, not a student’s ability, placement or comprehension.
- Why can another checker give a different answer?
- Sentence and word boundaries and which characters count as letters can differ between tools. This implementation counts letters and digits inside words; spaces and punctuation are shown separately and are not used by ARI.
- Can I score a book title, a PDF or a Word file?
- Paste the passage itself. There is no title database, file upload or Word integration. Scores are calculated locally for English text and do not supply Lexile, Accelerated Reader or a tested reading age.
Arithmetic follows the four printed formulas and the counting rules shown. English syllables are estimated by a heuristic rather than a dictionary, so Flesch-Kincaid grade and reading ease can differ from other checkers. Correct any word’s syllable count by hand. These scores describe text, not a reader’s ability.