Contrast (Enhanced)
AAA-level contrast: 7:1 for body text, 4.5:1 for large text. Stricter than 1.4.3, intended for users with significant low vision who need higher contrast to read comfortably.
What it asks
At AAA, body text must hit 7:1 contrast and large text (18pt / 14pt bold) must hit 4.5:1. Same exemptions as 1.4.3 — logos, decorative text, inactive controls — but the bar is roughly twice as strict. Designed for users with moderate to severe low vision, where 4.5:1 is still hard to read in poor lighting.
How to meet it
- Use a contrast checker that exposes both AA and AAA pass/fail; aim for the AAA column.
- For body text on white, a foreground darker than
#595959typically clears 7:1. - For dark mode, foreground lighter than
#b3b3b3on near-black typically clears. - Use pure black on pure white where brand allows — it’s the safest 21:1 ratio.
- Pair AAA contrast with a user toggle if the high-contrast mode would clash with brand on the default theme.
Common failures
- Mid-gray body text (
#666) that passes 4.5:1 but fails 7:1 — a near-miss is still a failure. - Brand-color CTA buttons that hit 4.5:1 but not 7:1 — most don’t.
- High-contrast theme that fails non-text contrast (1.4.11) even though text contrast passes.
Why it matters
AAA is rarely required contractually, but high-contrast theme support is increasingly expected in government and assistive-tech-heavy contexts. The cleanest path is to offer an opt-in high-contrast theme that meets 7:1 without forcing the default theme away from brand.