Readability Formulas

Input—per 1M tokens

Output—per 1M tokens

Context—tokens

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About

Readability Formulas is ranked #6 of 26 in AI readability checkers on Inferse. It runs on Browser extension, macOS, Web, Windows. There is a free plan.

Compared on AI readability checkers

Free plan: Yesreadabilityformulas.com

Facts

Purpose: The site offers free tools to score text and identify the reading and grade levels readers need to understand it.readabilityformulas.com · 2 Oct 2026
Readability scoring: The Readability Scoring System scores English-language text using popular readability formulas and estimates reader grade level and age.readabilityformulas.com · 2 Oct 2026
Formula selection: The system includes formulas such as Flesch Reading Ease, Flesch-Kincaid, Gunning Fog, SMOG, Dale-Chall, Spache, FORCAST, Fry, and Raygor.readabilityformulas.com · 2 Oct 2026
File inputs: The system accepts .txt, .docx, .rtf, .html, and .pdf files, as well as pasted text.readabilityformulas.com · 2 Oct 2026
Editor: The beta Robert Gunning Editor helps identify hard words and wordiness, with tools for editing phrases, nominalizations, fuzzy words, weak verbs, and more.readabilityformulas.com · 2 Oct 2026
Batch processing: Batch Processing is marked beta and can score multiple texts using one or more readability formulas.readabilityformulas.com · 2 Oct 2026
Text statistics: Text Statistics reports measures including syllable count, average sentence length, abbreviations, proper nouns, and passive voice.readabilityformulas.com · 2 Oct 2026
Browser extension: The extension for Google Chrome and Microsoft Edge can score highlighted website text, open the editor, and show word statistics.readabilityformulas.com · 2 Oct 2026
Privacy: The privacy policy says text processing runs through local scripts in the user's device browser and submitted text is not stored on a server or accessible to the site.readabilityformulas.com · 2 Oct 2026
Synonym Finder: The privacy policy says the Synonym Finder connects securely to Datamuse's API and can transmit one word at a time.readabilityformulas.com · 2 Oct 2026
Support: The site asks users to contact it about difficulties, bugs, mistakes, or scoring discrepancies.readabilityformulas.com · 2 Oct 2026
Intended users: The site names writers and editors, educators, marketing professionals, healthcare providers, and government agencies as users who may benefit.readabilityformulas.com · 2 Oct 2026