Large text contrast checker
Large text (18pt / 24px or bold 14pt / ~19px) benefits from looser WCAG contrast requirements because it is easier to read at lower contrast ratios. Check whether your colours meet the 3:1 (AA) or 4.5:1 (AAA) threshold for large text.
| Contrast ratio | 21.00 : 1 |
| AA. Large text (≥3:1) | pass |
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PRESETS
How it works
WCAG contrast is computed using relative luminance: each sRGB channel is linearised (gamma-corrected), then combined as L = 0.2126R + 0.7152G + 0.0722B. The ratio is (L1 + 0.05) / (L2 + 0.05) where L1 is the lighter colour. APCA uses the separate APCA-W3 0.0.98G algorithm which accounts for polarity and produces an Lc value. All computation runs entirely in your browser.
Processing runs in your browser
All contrast calculations happen in your browser tab. Our servers are not involved at any point.
Related operations
To swap a HEX value into RGB or HSL while testing, try the colour converter. For generating an accessible swatch set from a brand colour, use the colour palette generator. To create lighter or darker variants that still pass contrast, see tints and shades.
Frequently asked questions
- What counts as 'large text' in WCAG?
- Large text is defined as at least 18pt (24px) in regular weight, or at least 14pt (~18.67px) in bold weight. Logos and decorative text are exempt from contrast requirements.
- Why is the threshold lower for large text?
- Larger glyphs are easier to read even at lower contrast because there is more visual information per character. WCAG accounts for this with a lower minimum ratio.