Embed the widget

Add the readability calculator to your site

A free, no-account, no-API-key embeddable widget. Drop one iframe tag into your blog, knowledge base, or content tool. Light or dark mode. Six readability formulas. Zero ongoing maintenance.

Live preview

Copy-paste embed snippet

Drop this anywhere HTML works — Wordpress custom HTML block, Ghost HTML card, Notion HTML embed, MDX file, plain blog post. Substitute the height to taste.

Light or dark mode

The widget auto-detects the visitor's system preference. To force a specific theme, append ?theme=light or ?theme=dark to the iframe src:

Attribution

The widget includes a small "readabilitycheck.com" link in its footer. We ask that you keep it visible. The snippet above also includes a one-line attribution paragraph below the iframe — it is not strictly required but is appreciated and helps the project stay free.

Who this is for

Writers and editors publishing content style guides who want readers to score their drafts in-page.
Content marketing teams producing readability-focused educational content.
SEO consultants embedding the tool in client deliverables and audits.
Plain-language and accessibility advocates linking from policy pages.
Educators teaching writing and editing — embed once, use across lesson plans.
Healthcare and government writing teams publishing internal style guidance.

Technical notes

The widget runs entirely client-side. The text a visitor pastes never leaves their browser.
No API key, no account, no rate limiting.
The iframe is sandboxed — it cannot read or modify the parent page.
The widget loads about 30 KB of JS and CSS plus one Google Fonts request (Geist).
Server response is gzipped and globally cached on Cloudflare's edge.
The widget sets noindex so it will not appear separately in search results.
Content-Security-Policy frame-ancestors * means any site can embed it.

No API key, no rate limit, no signup

The embed is free forever. If you'd like a JSON API for server-side scoring (instead of an embedded widget), email [email protected] — we're prioritising features based on demand.