Color contrast checker
WCAG contrast ratio for text vs background. AA/AAA checks, preview, copy, and share link.
Preview
The quick brown fox jumps over the lazy dog
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This tool runs only in your browser. It does not upload your colors or text.

Tip: “Share link” encodes your inputs in the URL hash so you can reopen the same check.

Contrast ratio
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Normal text
AA—
AAA—
Large text
AA—
AAA—
Suggestion
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Formula
(L1 + 0.05) / (L2 + 0.05), where L1 ≥ L2 (relative luminance)
About / 關於

Color contrast checker (WCAG) — Check WCAG contrast ratio between text and background colors. Supports HEX/RGB input, AA/AAA checks, preview, and shareable links. Browser-only MVP.

Example: Use this tool to sanity-check numbers quickly, then share the link if you need to discuss with others.

FAQ: (1) Does it upload my data? No—runs in your browser. (2) Can I share results? Yes—use the share link feature. (3) Is it authoritative? Treat it as a convenience, not professional advice.

色彩對比度檢查器（WCAG） — 檢查文字/背景的 WCAG 對比度：支援 HEX/RGB、AA/AAA 判斷、預覽，以及可分享連結。純前端 MVP。

範例：用這個工具快速試算與對照結果，需要討論時再把連結分享給對方。

FAQ： (1) 會上傳資料嗎？不會，計算在瀏覽器內完成。 (2) 能分享結果嗎？可以，用分享連結。 (3) 準確嗎？請把它當作便利工具，不是專業建議。