About ContrastLab — Free Accessibility Tools

ContrastLab is a free online toolkit built for designers, developers, bloggers, and content creators who care about accessibility and readability. We offer three focused tools a color contrast checker, a font pairing generator, and a text readability checker that run entirely in your browser with no signup, no downloads, and no cost. The project started in 2026 as a response to a simple problem: accessibility tools were either paid, fragmented, or too technical for everyday use.

Why ContrastLab Exists

Most accessibility and typography tools fall into two camps: enterprise software with a subscription, or single-purpose checkers that do one thing and stop. A designer checking WCAG contrast has to open one tab, then a different tool for font pairing, then a third for readability. None of them talk to each other, and most require an account.

ContrastLab was built to close that gap. The idea is straightforward: if you are building a website, a blog post, or a product listing, you should be able to verify the three most common readability problems color contrast, font choice, and text difficulty in one place, for free, without friction.

The tools are intentionally lightweight. They run in the browser, they do not store your input, and they do not ask for an email address. That decision is deliberate: accessibility checks should be fast enough to run before you publish, not a separate project you schedule for later.

What We Build

ContrastLab currently offers three tools, each focused on a specific readability problem.

Color Contrast Checker
Tests any foreground and background color pair against WCAG AA and AAA standards. It reports the exact contrast ratio, flags pass/fail at normal and large text sizes, and supports hex, RGB, and opacity values. The tool also includes an image pixel sampler for text over photos.

Font Pairing Generator
Previews Google Fonts combinations at real heading and body sizes. Pick a category (sans, serif, display, or script), select a heading and body font, adjust the size sliders, and copy the production-ready CSS. The tool flags weak pairings such as using the same font for both roles so the output is usable without a second check.

Text Readability Checker
Pastes any text and returns Flesch Reading Ease, Flesch-Kincaid Grade Level, Gunning Fog, SMOG, ARI, and Dale-Chall scores in a single pass. It also reports word count, sentence count, syllables, and complex words, so you can see exactly which sentences are dragging the score down.

All three tools are free, require no account, and run on any device with a browser.

Who ContrastLab Is For

The tools are built for people who publish content and want it to be readable, not for enterprise accessibility audits.

Web designers and developers use the contrast checker before shipping a component, and the font pairing generator when setting up a new design system.

Bloggers and content writers run drafts through the readability checker to catch sentences that are too long or too dense before publishing.

E-commerce sellers check product listing text for readability and contrast, especially on image overlays where white text over photography is a common failure point.

Students and educators use the readability checker to assess reading levels of essays or teaching material.

If you are building something that people read on a screen, the tools are for you.

How the Tools Work (and What They Do Not Do)

Every ContrastLab tool runs entirely in your browser using JavaScript. No text, color value, or image you paste is sent to a server. Nothing is stored. When you close the tab, the data is gone.

The scores and ratios are computed using the same published formulas used by accessibility auditors and readability researchers. The contrast checker applies the WCAG 2.1 relative luminance formula. The readability checker applies the standard Flesch, Flesch-Kincaid, Fog, SMOG, ARI, and Dale-Chall equations.

What the tools do not do: They do not replace a human judgment. A contrast ratio of 4.5:1 passes WCAG AA, but whether the design looks right is still your call. A readability score of grade 8 is a guideline, not a guarantee that the content is clear. The tools measure specific, countable properties. They do not measure whether the writing is good, the design is appropriate, or the content is accurate.

That distinction matters. ContrastLab is a diagnostic toolkit, not an automated auditor.

Contact

ContrastLab is a small, independent project. For questions, feedback, or tool suggestions, use the contact form on the site. We read every message, though response times vary.