Dimension scores are derived from public data and fields; weighted into the composite. Reference only.
Readability Check is a free English readability calculator for writers, editors, SEO professionals, educators, healthcare communicators, and government plain-language use cases. It is not a grammar checker or an AI writing assistant. Instead, it calculates text difficulty using published formulas and converts the results into U.S. school grade levels, helping you judge whether your target readers can easily understand the content.
The tool provides six commonly used industry formulas: Flesch Reading Ease, Flesch–Kincaid, Gunning Fog, SMOG, Coleman–Liau, and Automated Readability Index, along with a consensus grade. Unlike tools that only show a single overall score, it highlights sentences in green, amber, and red, calling out long sentences over 25 words, borderline sentences of 16–25 words, and complex words. Clicking a sentence displays specific revision suggestions. According to the official description, its scoring engine, syllable counting, sentence segmentation, and formula calculations all run in the browser; text is not uploaded, stored, or logged. After the page loads, it can even continue working offline. The implementation is hand-written JavaScript, with no React, Vue, or build step. The page is under 60KB and hosted on Cloudflare Pages.
Pricing is very straightforward: there is no paid tier, no registration, no API key, and no usage limit. The calculator itself has no ads, while reference pages are supported by display ads. Integration is mainly through an iframe widget, which can be embedded in WordPress, Ghost, Notion, MDX, or standard HTML pages. It supports light and dark themes and has no rate limits. Note that the main content does not show an official JSON API or SDK; if you need server-side scoring, the only option is to contact them by email to express your requirements.
Its strengths are that it is free, privacy-friendly, transparent about its formula sources, and offers sentence-level highlighting that directly guides rewriting. It is especially useful for patient-facing healthcare materials, government plain-language content, marketing pages, blogs, and internal policy reviews. Its limitations are also clear: it does not handle grammar, style, passive voice, or AI rewriting. It also does not state support for Chinese or other non-English text, does not disclose an open-source repository or self-hosting option, and lacks batch processing, team collaboration, and history tracking.
The site’s hosting and accessibility are not specified in the main content, so availability in mainland China should be marked as unknown. Payment is not an issue because there is no paid plan. If you need stronger writing-style suggestions, compare it with Hemingway Editor. If you need a grammar and spelling ecosystem, consider Grammarly. If you work in SEO or office software, you can also use Yoast readability score or Microsoft Word’s readability statistics.
⚠ This review is compiled from public sources and does not constitute a purchase recommendation. Verify all facts on the vendor's official site. Verify on readabilitycheck.com official site.
readabilitycheck.com is an United States Dev Tools provider. TG4G tracks its product information, an overall rating of 7.0/10, and a China-accessibility score of China direct-connect friendly. Click "Visit Official Site" to reach readabilitycheck.com directly.