Automated Readability Index Calculator
Paste text to get its Automated Readability Index, a US grade level based on characters per word and words per sentence. Because it counts characters, the score is exact.
How to calculate the Automated Readability Index
- Paste or type your text into the box.
- Read the ARI value and the US grade or age band it maps to.
- Review the character, word and sentence counts, then edit and retest.
Examples
Score a simple sentence
The quick brown fox jumps over the lazy dog.
ARI about 1.4 (Grade 1 to 2)
Frequently asked questions
How is the Automated Readability Index calculated?
The formula is 4.71 times characters per word plus 0.5 times words per sentence minus 21.43. The result is rounded up to a US grade level.
What counts as a character?
Letters and digits only. Spaces and punctuation are not counted, so the score depends on how long the actual words are.
Why is ARI exact when other scores are estimates?
ARI uses character counts instead of syllables. Characters are counted precisely, so there is no phonetic guessing and the result is fully determined by the text.
How does ARI compare to Flesch-Kincaid?
Both return a US grade level. ARI uses characters per word while Flesch-Kincaid uses syllables per word, so the two grades are usually close but not identical.
Is my text private?
Yes. The score is computed in your browser and nothing is uploaded or stored.
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