Why color contrast matters
Text with low contrast against its background is hard to read for many people, including those with low vision. The WCAG (Web Content Accessibility Guidelines) define minimum contrast ratios to ensure readability.
Criteria used
AA (minimum recommended): 4.5:1 for normal text, 3:1 for large text (18pt and up, or 14pt bold). AAA (stricter level): 7:1 for normal text, 4.5:1 for large text.
Frequently asked questions
Which level should I follow, AA or AAA?
AA is the minimum standard required by most accessibility regulations; AAA is stricter and recommended for essential content.
Does the contrast ratio change depending on font size?
The contrast ratio calculation itself doesn't change — what changes is the minimum required threshold: large text (18pt and up, or 14pt bold) has a lower threshold because it's naturally easier to read.