What is WCAG AA vs AAA?

WCAG AA requires 4.5:1 for normal text and 3:1 for large text. AAA (the enhanced level) requires 7:1 and 4.5:1. Most accessibility standards and legal requirements reference AA.

What counts as large text?

WCAG defines large text as 18pt (24px) or larger, or 14pt (approximately 18.67px) bold or larger.

Is this tool free to use?

Yes. All Skybin developer tools are free with no account, API key, or usage limits.

Does my data get sent to a server?

No. Processing runs in your browser whenever possible. Sensitive input never leaves your device unless a tool explicitly fetches a URL you provide (e.g. OG Validator).

Can I use this on mobile?

Yes. The tools work in modern mobile browsers, though a desktop screen is easier for large JSON or PDF workflows.

How is this different from desktop apps?

There is nothing to install or update. Open a bookmarked URL and start working — ideal for quick tasks during development or support calls.

Are there keyboard shortcuts?

Most tools support standard paste (Ctrl+V / Cmd+V) and select-all in text areas. Copy buttons provide one-click output.

Does Skybin store my history?

No. We do not log tool inputs or outputs. Refreshing the page clears in-memory state unless the tool encodes state in the URL.

免费工具

Color Contrast Checker

Check contrast ratios between foreground and background colors. See WCAG 2.1 AA and AAA compliance for normal and large text instantly.

Color Contrast Checker

Text color (foreground)

Background color

The quick brown fox

Normal text

Contrast ratio: 14.10:1

Contrast Ratio

14.10:1

WCAG AA

Normal text

Pass

WCAG AAA

Normal text

Pass

WCAG AA Large

Large text

Pass

WCAG AAA Large

Large text

Pass

Why contrast ratio matters

Sufficient color contrast ensures text remains readable for users with low vision or color blindness. WCAG 2.1 Level AA (the standard required by most accessibility laws) requires a 4.5:1 ratio for normal text and 3:1 for large text (18px+ or 14px+ bold).

Why use Color Contrast Checker online?

Color Contrast Checker in the browser saves context switching: no CLI install, no fragile one-liners, and instant feedback for teammates who do not live in the terminal. It is ideal for debugging, demos, and quick checks during code review.

Tips for best results

Work with a sample payload first, then paste production data. Keep privacy in mind: prefer local browser processing for secrets, tokens, and customer data. Bookmark this page for faster access next time.

How to use

Pick your text color using the color picker or enter a hex value.
Pick your background color the same way.
Read the contrast ratio and WCAG pass/fail badges instantly.
Use the presets for quick reference pairs.
Click Copy CSS to grab the color pair as CSS properties.
Review the output and use Copy to paste into your editor, ticket, or chat.
Need another utility? Scroll to Related Tools below for Color Contrast Checker companions on skybin.io.
For a deeper walkthrough, read the linked Skybin blog article at the bottom of this page.

在线工具与终端对比

终端 / CLI	本工具
Install CLI tools or write a one-off script	Open the tool in your browser — no install
Look up flags in man pages or Stack Overflow	Paste input or upload files where supported
Repeat for each file format or edge case	Get instant visual feedback and copy buttons

All calculations happen in your browser — no color data is sent to any server.

来自 Skybin 博客

Free developer tools from Skybin

在 Skybin 阅读指南

常见问题

What does Color Contrast Checker do?: Check contrast ratios between foreground and background colors. See WCAG 2.1 AA and AAA compliance for normal and large text instantly.
What is WCAG AA vs AAA?: WCAG AA requires 4.5:1 for normal text and 3:1 for large text. AAA (the enhanced level) requires 7:1 and 4.5:1. Most accessibility standards and legal requirements reference AA.
What counts as large text?: WCAG defines large text as 18pt (24px) or larger, or 14pt (approximately 18.67px) bold or larger.
Is this tool free to use?: Yes. All Skybin developer tools are free with no account, API key, or usage limits.
Does my data get sent to a server?: No. Processing runs in your browser whenever possible. Sensitive input never leaves your device unless a tool explicitly fetches a URL you provide (e.g. OG Validator).
Can I use this on mobile?: Yes. The tools work in modern mobile browsers, though a desktop screen is easier for large JSON or PDF workflows.
How is this different from desktop apps?: There is nothing to install or update. Open a bookmarked URL and start working — ideal for quick tasks during development or support calls.
Are there keyboard shortcuts?: Most tools support standard paste (Ctrl+V / Cmd+V) and select-all in text areas. Copy buttons provide one-click output.
Does Skybin store my history?: No. We do not log tool inputs or outputs. Refreshing the page clears in-memory state unless the tool encodes state in the URL.