Automated Readability Index Calculator
ARI grade level for a pasted text — letters and words only, so no syllable guess enters the result.
What is Automated Readability Index?
The Automated Readability Index was designed for the era of typewriters, where counting keystrokes was easier than counting syllables, and it keeps the virtue that came with that: it uses letters instead of syllables, so nothing in it is estimated. Where the other four formulas inherit the error of a heuristic syllable counter, ARI is exact — it will return the same grade every time on the same text. The trade is that length is all it knows: a passage of long simple words scores as harder than it reads, and a passage of short technical words scores as easier.
How it works
The score is 4.71 times the average letters per word plus 0.5 times the average sentence length, minus 21.43, and letters are counted as alphabetic characters only — digits, punctuation and spaces are excluded, matching the keystroke counting the index was built on. Because it needs no syllable guess it is the reference the other formulas can be sanity-checked against: when ARI and Flesch-Kincaid disagree by more than a grade or two, the words in the text are either longer than they are difficult, or shorter than they are hard.
- Enter your input. Type or paste your input into the field above — the tool responds instantly.
- Review the result. Output updates live as you type. Everything runs entirely in your browser.
- Copy or download. Use the Copy button to grab the result, or Download to save it as a file.
Examples
Realistic sample
Type or paste any realistic input — the tool computes the result locally and instantly.
Common mistakes
Expecting a server round-trip
Nothing is uploaded — every tool in this category runs entirely in your browser.