The Automated Readability Index, or ARI, outputs a US grade level based on characters per word and words per sentence, which makes it fast and objective since it never has to guess syllables. The formula is 4.71 times the average characters per word plus 0.5 times the average words per sentence minus 21.43. Because it counts characters directly, ARI is popular in software and typewriter era tools where letter counts were trivial to gather. A score of 8 lines up with an eighth grade reading level, and the result rounds to the nearest whole grade for a clear target. This calculator recomputes the moment you edit your text and runs entirely in your browser, so your draft is never uploaded. Use it alongside other readability scores to confirm your writing hits the right audience level before you publish.
The Automated Readability Index uses characters per word and words per sentence to output a US grade level, with no syllable counting.
Because it relies on character and word counts rather than syllables, it is easy to compute consistently for any text.
An ARI of 8 corresponds roughly to an eighth grade reading level, meaning a typical eighth grader can read the text.
The Automated Readability Index, or ARI, outputs a US grade level based on characters per word and words per sentence, which makes it fast and objective since it never has to guess syllables. The formula is 4.
Yes. Automated Readability Index Calculator is completely free, with no sign-up and no usage limits.
Yes. Automated Readability Index Calculator runs in any modern web browser. There is nothing to download or install.
Yes. Automated Readability Index Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.