Just Tool It
Just Tool It / WCAG Contrast Checker
On-device — nothing uploaded

WCAG Color Contrast Checker

Compute WCAG 2.x AA / AAA contrast ratios between any two colors.

The quick brown fox jumps over the lazy dog.

The quick brown fox jumps over the lazy dog. — 14px regular

21.00
: 1 contrast ratio
Level Normal text (≥4.5:1 AA, ≥7 AAA) Large text (≥3 AA, ≥4.5 AAA)
AA — —
AAA — —
UI components / graphics (AA 3:1) —

Large text = 18pt regular or 14pt bold (about 24px / 18.66px).

Why use WCAG Contrast Checker in your browser?

Passwords, hashes, and secrets should never transit a backend. WCAG Contrast Checker: Compute WCAG 2.x AA / AAA contrast ratios between any two colors. Server-side tools upload or log inputs. Just Tool It does not: it uses Web Crypto and local utilities so passwords and secrets never transit a backend. Close the tab and the working data is gone. That is zero-server processing and on-device security.

How to use WCAG Contrast Checker

  1. Open the tool on this page — no account or email required.
  2. Add your input by dropping a file, pasting text, or filling the form fields.
  3. Adjust options if available (quality, format, ranges, etc.).
  4. Run the tool and download (or copy) the result. Nothing was uploaded to Just Tool It.

Frequently asked questions

Is my data uploaded when I use WCAG Contrast Checker?
No. Just Tool It is a static web app. Your input is processed with Web Crypto and local utilities so passwords and secrets never transit a backend. You can verify in the browser Network panel: no file payloads are sent to our origin for processing.
Is this tool free? Do I need an account?
Yes, it is free. There is no sign-up, paywall, or trial. We do not create user accounts because we never receive your files.
Does it work offline?
After the page and any required libraries are cached (including via the service worker / PWA), many tools keep working without a network. Large optional engines such as FFmpeg.wasm or OCR models still need a one-time download.
How is this different from other free online tools?
Most free tools upload files to a cloud worker. Just Tool It emphasizes zero-server processing and on-device security: files stay in browser memory until you download the output and close the tab.