This is standard body copy text designed to evaluate accessibility contrast compliance under WCAG 2.1 AA (4.5:1) and AAA (7.0:1) requirements. Ensure your UI typography remains clearly readable for all users.
Our free Contrast Checker enables web designers, accessibility auditors, and front-end engineers to verify text legibility and color contrast ratios against WCAG 2.1 AA and AAA guidelines. Computes relative luminance across sRGB gamma-linearized color spaces using ITU-R BT.709 weighting (0.2126R + 0.7152G + 0.0722B) for text, headings, buttons, and UI components. Features a live multi-element text preview canvas, EyeDropper screen sampling, 1-click color swapper, and a smart contrast fixer that auto-suggests compliant HEX colors—executing 100% in local browser JavaScript with zero server transmission.
Select text and background colors using color pickers, HEX inputs, or the EyeDropper tool.
View the live text preview across headings, body copy, and buttons while checking the numerical contrast ratio.
Review the 5 WCAG 2.1 AA/AAA badges. If contrast fails, click an auto-suggested passing color.
Renders your exact foreground and background colors across headings, body copy, form labels, and UI buttons in real time.
Evaluates 5 distinct accessibility standards simultaneously, certifying compliance for normal body text, large display type, and UI graphic components.
Recommends adjusted lighter or darker color variations when ratios fall short of WCAG AA, executing 100% locally in your browser with zero server transmission.
The Web Content Accessibility Guidelines (WCAG 2.1) specify color contrast as the ratio of relative luminance between two colors. Relative luminance (L) measures perceived brightness normalized from 0 (pure black) to 1 (pure white). Before calculating luminance, sRGB color values must be converted from non-linear gamma-encoded space into linear light intensities using the piecewise linearisation equation: V = c ≤ 0.03928 ? c / 12.92 : ((c + 0.055) / 1.055)^2.4.
Once linearized, the R, G, and B channels are weighted using ITU-R BT.709 spectral efficiency factors: L = 0.2126 * R + 0.7152 * G + 0.0722 * B. The contrast ratio between two colors is then calculated as (L1 + 0.05) / (L2 + 0.05), where L1 is the lighter color. Adding 0.05 accounts for ambient light scatter and prevents division by zero. Standard text requires at least 4.5:1 for Level AA and 7.0:1 for Level AAA compliance.
When color combinations fall below accessibility thresholds, our Smart Contrast Fixer evaluates your base hue in HSL space and automatically computes nearest-neighbor lightness values that pass WCAG AA (4.5:1) or AAA (7.0:1). This allows UI/UX designers to preserve original brand identity while guaranteeing screen legibility across mobile displays, high-glare environments, and assistive reading technology.
(L1 + 0.05) / (L2 + 0.05), where L1 is the relative luminance of the lighter color. Channels are first linearized from sRGB gamma encoding and weighted with ITU-R BT.709 coefficients (0.2126R + 0.7152G + 0.0722B).