Overview

The Readability Scoring System estimates the grade level and age a reader may need to understand a text. You can paste text or upload .txt, .docx, .rtf, .html, and .pdf files, which makes it useful for checking both drafts and existing documents. Sentence analysis and clarity recommendations can help guide revision, though a readability score is a signal rather than a complete judgment of whether writing suits its audience.

Privacy is a notable consideration for sensitive material: the 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 different: it connects to Datamuse's API and may transmit one word at a time.

Key features

Multiple scoring formulas

The scoring system includes Flesch Reading Ease, Flesch-Kincaid, Gunning Fog, SMOG, Dale-Chall, Spache, FORCAST, Fry, and Raygor. Comparing several measures can help editors and educators see how different formulas assess a passage, but interpreting the results still takes judgment about audience and context.

Editing and statistics

The beta Robert Gunning Editor identifies hard words and wordiness, with tools for phrases, nominalizations, fuzzy words, weak verbs, and more. It provides a path from diagnosis to revision, but beta status makes it a less convincing choice for teams that need a settled editing workflow. Text Statistics adds syllable count, average sentence length, abbreviations, proper nouns, and passive voice.

Batch processing and browser extension

Batch Processing is also marked beta and can score multiple texts with one or more formulas, a useful option when reviewing a group of documents rather than one passage at a time. The Chrome and Edge extension scores highlighted website text, opens the editor, and shows word statistics, bringing checks into browser reading and research.

Pricing

The Free online readability tools plan costs 0.00 USD per free and includes free calculators and the Readability Scoring System. It suits individuals who need scoring and text checks without a paid commitment; there is no paid tier to weigh against it in the plan presented. Its English-only scope and beta status for the editor and batch feature are the main trade-offs, rather than a stated usage cap.

Platforms

Readability Formulas is available on the web, macOS, Windows, and as a browser extension. The extension works with Google Chrome and Microsoft Edge. English is the supported language, so multilingual workflows need another tool.

Who it's for

Writers and editors can use the formulas, statistics, and editing tools to identify passages that may need revision. Educators can compare reading difficulty, while marketing professionals, healthcare providers, and government agencies may find the scoring useful when preparing audience-facing material. It is less suitable for anyone who needs language coverage beyond English or depends on non-beta batch editing.

Pros and cons

Pros: A broad selection of formulas makes it possible to compare different readability measures rather than rely on one score.
Pros: File uploads, pasted text, statistics, and browser-based checks accommodate several ways of reviewing content.
Pros: Local browser processing and no server storage of submitted text offer a privacy advantage for the scoring workflow.
Cons: English-only support rules it out for multilingual review.
Cons: The editor and batch processing are beta, so they may not suit workflows that need established production tools.
Cons: The Synonym Finder can transmit a queried word to Datamuse, unlike the local text-processing workflow.

Alternatives

ProWritingAid is a freemium option for writers who want a browser extension and daily editing tools, with its free plan capped at 500 words per report run and two report runs per day.

TextGears is worth considering when API or web access and unlimited checks, translations, and paraphrases of long texts matter; its PRO plan starts at 2.48 USD per month.

Check Readability suits readers looking for a free web or extension checker with no account or usage fees.

Text Inspector may fit users who want a web or API tool with a free 250-word allowance and automatic deletion after six hours.

AnchorKite Readability Checker is a free web option for users who prioritize no signup and offline use after loading.

Delimiter Readability Checker is another free web checker for readers who want to avoid accounts and paywalls.

Hemingway Editor is an alternative for users who want a macOS, Windows, or web editor with paid plans that include monthly AI sentence allowances.

Slick Write is a free web alternative for checking submissions of up to 200,000 characters.

Readability Checkers and AI Readability Checkers offer broader category comparisons.

Verdict

Choose Readability Formulas if you need free, English-language readability scoring across several established formulas, supported by statistics and file inputs. Its main advantage is the range of measures available without a subscription; look elsewhere if your work depends on multilingual support or a dependable, non-beta editor and batch 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