APCA Contrast Check

Next-gen accessibility standard · Based on perceptual luminance, more accurate than WCAG 2.x

Text Color Background Color

Usage Scenarios

Scenarios based on current Lc value

Fix Suggestions

Select a suggestion to preview the value and apply to your project

Live Preview

Check headings, body text and buttons with the fixed colors

Lc Reference

Lc 90+ Ultra-high contrast · Any size/weight

Lc 75+ Body text · 16px+ regular

Lc 60+ Larger body · 18px+ or 14px bold

Lc 45+ Large text · 24px+ regular, 18px bold

Lc 30+ Display heading · 32px+, non-critical UI

Lc < 30 Decorative only, not suitable for text

WCAG uses a fixed ratio (4.5:1), which is too strict for light colors yet too lenient for dark. APCA distinguishes text/background polarity and gives precise requirements based on size and weight.

WCAG uses a fixed ratio (4.5:1), which is too strict for light palettes yet too lenient for dark ones. APCA accounts for text/background polarity and gives precise requirements based on font size and weight, better reflecting human visual perception.

→ Switch to WCAG Contrast Fix

Output

Apply fixed colors to your project

About APCA Contrast Checker

Check text contrast with APCA — the perceptual algorithm behind WCAG 3.0. More accurate than WCAG 2.x. Evaluate body text, headings, and UI elements instantly. Every calculation happens locally in your browser, so the Lc score updates instantly as you tweak a color — no round-tripping through a separate checker.

Reach for it when auditing an accessibility handoff, especially for thin font weights and small type sizes where the older WCAG 2 ratio tends to give false passes.

Common questions

What is APCA contrast? APCA (Advanced Perceptual Contrast Algorithm) is the contrast method behind WCAG 3.0. It models real-world text legibility more accurately than the older ratio, accounting for text size and weight.

How is APCA different from the WCAG 2 ratio? WCAG 2 uses a fixed luminance ratio; APCA outputs an Lc value (0–106) and adjusts requirements by font size and weight, so thin small text needs more contrast than bold large text.

What Lc value do I need? As a guide, Lc 75+ for body text, Lc 60 for larger or secondary text, and Lc 45 for large headings. Higher is always safer.