📢 728×90 Ad
The quick brown fox
Small text sample — 14px regular weight
📢 300×250 Ad — Rectangle

About this tool

Contrast Checker calculates WCAG 2.1 contrast ratios using the official relative luminance formula, reporting AA and AAA compliance for normal and large text. Accessible contrast is a legal requirement in many jurisdictions. All calculations run entirely in your browser — no data is transmitted.