Overview

The Readability Scoring System estimates the grade level and age readers may need to understand a text. Users can paste text or upload .txt, .docx, .rtf, .html, and .pdf files. Sentence analysis and clarity recommendations help put scores in context, but readability formulas are signals for revision rather than a complete measure of whether writing suits its audience.

Key features

Scoring and editing

Readability Formulas includes Flesch Reading Ease, Flesch-Kincaid, Gunning Fog, SMOG, Dale-Chall, Spache, FORCAST, Fry, and Raygor. Comparing several formulas can help editors and educators spot how different measures assess a passage, though interpreting the results still takes editorial judgment.

The beta Robert Gunning Editor flags hard words and wordiness, with tools for phrases, nominalizations, fuzzy words, weak verbs, and more. It offers a route from diagnosis to revision, but its beta status makes it less suitable as the foundation of a polished, dependable editing workflow.

Statistics, batches, and browser checks

Text Statistics reports syllable count, average sentence length, abbreviations, proper nouns, and passive voice. Batch Processing, also marked beta, can score multiple texts with one or more formulas, a useful fit for comparing a body of material rather than handling documents one at a time.

The Chrome and Microsoft Edge extension scores highlighted website text, opens the editor, and shows word statistics. This brings checks to browser-based reading and editing; the scoring system also accepts common document formats, so users need not rely on the extension for their own files.

The privacy policy says text processing runs through local scripts in the user's browser and submitted text is not stored on a server or accessible to the site. The Synonym Finder is a separate exception: it connects securely to Datamuse's API and may transmit one word at a time. That distinction matters for users handling sensitive copy.

Pricing

The Free online readability tools plan costs 0.00 USD per free and includes free calculators and the Readability Scoring System. It is the natural starting point for occasional checks and users who want the core scoring tools without a subscription. The free-plan description does not give usage caps, so the stated price alone does not establish how much text or how many runs it supports.

Readability Formulas uses a freemium model, but the free plan is the only plan described here. Its beta editor and batch processing add useful capabilities, though the plan description does not establish whether either has separate limits or paid options.

Platforms

The platform coverage includes web, macOS, Windows, and an extension. The Chrome and Microsoft Edge extension handles highlighted website text; the scoring tools accept pasted text and uploaded files. English is the supported language, so multilingual teams should choose a tool that explicitly covers their other languages.

Who it's for

Writers and editors can use the scores, statistics, and editor to identify passages to revisit. Educators can compare reading difficulty, while marketing professionals, healthcare providers, and government agencies may use the tools to assess text for intended readers. The free entry point makes it approachable for occasional use; teams with a formal batch workflow should weigh the beta status of Batch Processing.

Pros and cons

Pros: A broad set of named formulas lets users compare reading-difficulty estimates instead of depending on one score.
Pros: File uploads, browser checks, statistics, editing tools, and batch scoring cover several stages of text review.
Pros: The policy says submitted text is processed locally and not stored on a server, with a clear caveat for one-word Synonym Finder requests.
Cons: English-only support rules it out for teams that need readability scoring in other languages.
Cons: The editor and batch processing are beta, making them less reassuring for workflows that depend on mature production tools.
Cons: The free plan description gives no usage caps, so heavy users cannot judge its practical ceiling from the plan terms.

Alternatives

For a broader directory view, browse Readability Checkers or AI Readability Checkers.

Choose ProWritingAid if you want a writer-focused extension and can work within its free limits: 500 words per report run, two report runs per day, 10 Rephrases per day, and three Sparks per day. TextGears is a better fit for API or web access with unlimited checks, translations, and paraphrases of long texts on PRO at 2.48 USD per month, plus custom dictionary rules and an option not to store texts.

AnchorKite Readability Checker is a free web option that runs in-browser and works offline after loading, with no signup. Check Readability suits people who want a free extension or web tool with no account or usage fees and personal or commercial use. Delimiter Readability Checker is another free web choice, with no account requirement or paywall.

Text Inspector may suit users who need API access or a stated 250-word free allowance with automatic deletion after six hours. Slick Write offers a free web tool with a 200,000-character submission limit. Hemingway Editor is an alternative for users seeking a macOS, web, or Windows editor.

Verdict

Readability Formulas is a strong starting point for English-language writers, editors, educators, and organizations that want several scoring methods plus practical text statistics without paying for the core tools. Choose it for formula breadth and local text processing; look elsewhere if you need other languages or a mature, clearly bounded batch-editing workflow.

	AI Readability	Readability Formulas
Free plan	Yes	Yes
Free trial	No	No
Paid from	Free	Free
Open source	No	No
Platforms	Web	extension, macOS, Web, Windows
Free plan	Yes	Yes
Sentence complexity	Yes	—
Plain-language rewrites	Yes	—
Input formats	text	—

AI Readability vs Readability Formulas

AI Readability

Readability Formulas