Readability Desk Chrome Extension
Last updated 2026-10-15
Readability Desk for Chrome checks the text you select on any web page. Select a passage, right-click and choose Readability score, or click the toolbar icon. You get the same numbers as the readability score checker on this site, without copying and pasting.
Install: Readability Desk on the Chrome Web Store — free readability scores; optional AI rewrite plan ($3.99/month or $29.99/year).
Free and private
- Scores: Flesch Reading Ease, Flesch-Kincaid grade, Gunning Fog, SMOG, Coleman-Liau and the Automated Readability Index.
- Counts: words, sentences, syllables, average sentence length, complex words.
- Marked text: sentences of 25+ and 35+ words are coloured, and passive phrases are marked. The passive check is a pattern match and can be wrong in both directions; the passive voice checker page explains the limits.
- Private: all of this runs on your computer. The text is not sent anywhere.
- No account and no access to the sites you visit: the extension only reads the text you select, only when you ask.
Paid: AI rewrite to a grade level
Pick a target grade from 3 to 12 and the extension rewrites the text with shorter sentences and plainer words, then scores the result so you can see whether it got there. A paid plan includes 150 rewrites a month.
Only the text you choose to rewrite is sent to our server and on to Claude (Anthropic) to produce the rewrite. We do not store the text; we keep counts only, to enforce the monthly limit and a daily cost limit. Details are in the extension privacy policy.
| Free | Paid | |
|---|---|---|
| Six readability formulas, counts | Yes | Yes |
| Long sentences and passive phrases marked | Yes | Yes |
| Works offline, nothing sent anywhere | Yes | Scores yes; rewrite needs internet |
| AI rewrite to a target grade | No | 150 a month |
| Account needed | No | Payment login through ExtensionPay |
Payments are handled by ExtensionPay and Stripe; we never see your card details.
Limits
Readability formulas measure sentence length and word length, not meaning. Text in Google Docs, PDFs viewed in Chrome and some web apps cannot be read by an extension: paste it into the box in the popup instead. AI rewrites can change nuance; read the result before you use it.