WCAG color contrast checker
Compare text and background colors using the WCAG relative-luminance formula. Enter two six-digit sRGB hex colors to see the contrast ratio and separate AA normal, AA large and AAA normal text checks.
Free to use. No email or account required.
Your inputs
The editable example is illustrative. Enter your own dimensions, operating data, prices, and fees. Results update as you edit.
Calculations run in your browser. Inputs are not saved or sent to analytics.
How it works
- → L₁; → L₂
- Contrast ratio (x:1) = (max(L₁, L₂) + 0.05) ÷ (min(L₁, L₂) + 0.05)
- L = 0.2126 × R + 0.7152 × G + 0.0722 × B
- Worked example
- #000,000 + #ffffff → 21:1; #ffffff + #ffffff → 1:1
Input and formula key
Your result
Complete the inputs to see your result.
Assumptions and limitations
AA normal requires 4.5:1, AA large 3:1 and AAA normal 7:1. Large text is at least 18 point, or 14 point bold. Decisions use unrounded ratios. Opaque solid sRGB colors only: transparency, gradients, images, focus states and full accessibility conformance require separate checks.
Sources
- W3C — WCAG 2.2 contrast and relative luminance Sources reviewed: 2026-10-28
Processing and privacy
The calculation or transformation runs in your browser. The tool does not send its input values or generated output to an application server. Loading a page still makes infrastructure requests; optional analytics and Google consent messages have separate controls.
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Sources and maintenance
Maintained by emonster. Sources are listed with their own review dates; these are not live-data timestamps or claims of independent expert certification.
