WCAG 3.0 APCA Contrast Checker
Evaluate color contrast for digital products utilizing the Advanced Perceptual Contrast Algorithm (APCA) designated for WCAG 3.0.
Configure Colors
Standard Templates
APCA Accessibility Guidelines
Live Preview Rendering
The quick brown fox jumps over the lazy dog.
Modern typography standards call for perceptual color measurements.
APCA differs from standard WCAG 2.0 formulas by accounting for display characteristics, font weight, background luminance, and spatial frequency. This ensures that text remains readable in both dark and light modes.
About apca contrast free
Check text contrast with APCA, the perceptual contrast method proposed for the draft WCAG 3, with thresholds for body text, headings and labels. APCA — the Accessible Perceptual Contrast Algorithm — scores text contrast as a lightness value (Lc) that accounts for text size and weight, and for whether the text is dark-on-light or light-on-dark. The WCAG 2 contrast ratio ignores both. APCA is the method proposed for WCAG 3, which is still a working draft, so use it as a design aid alongside the WCAG 2 ratio rather than as a compliance test.
How to Use This Tool in 3 Easy Steps
Choose two colors
Set the text color and the background color, or start from a template.
Read the Lc score
See the perceptual contrast value for that exact pairing and polarity.
Check it against use
Compare the score with the threshold for small body text, regular text, headings or labels.
Why Users Choose SolveMyPDF
- ✓Thresholds by use: Lc 75+ for small body text, 60+ for regular text, 45+ for large headings and 30+ for non-content labels.
- ✓Polarity-aware: Swapping text and background changes the score, because light-on-dark is perceived differently.
- ✓Live preview: See sample text in your chosen colors at several sizes while you adjust them.
- ✓Starter templates: Common UI pairings to compare your palette against.
Frequently Asked Questions
Is APCA part of WCAG?
Not yet. It is the contrast method proposed for WCAG 3, which remains a working draft. Most accessibility regulations and procurement standards currently reference WCAG 2.x, whose AA level asks for a 4.5:1 ratio for normal text — so check both.
Why does the score change when I swap the two colors?
APCA is polarity-aware: the same pair of colors reads differently as dark text on a light background than as light text on a dark one. The WCAG 2 ratio gives an identical number either way.
What do the Lc thresholds mean in practice?
Higher is more readable. Small or thin body text needs the most contrast (around Lc 75), while large headings can work at around Lc 45 and decorative or non-content labels lower still.