Alternative Text (Content Equivalence)

Alternative text is WCAG's first and most fundamental requirement — Success Criterion 1.1.1, at Level A, the minimum standard. Every image, icon, or non-text element that conveys meaning must have a text alternative carrying the same information.

Alternative text is WCAG's first and most fundamental accessibility requirement — Success Criterion 1.1.1, Level A, the minimum standard. Despite being the most widely understood accessibility principle, WebAIM's Million 2025 report found alt text missing on 55.5% of pages, making it the second most prevalent accessibility violation after low-contrast text. The impact is direct: for blind and low-vision users navigating with screen readers, an image without alt text is either invisible (silent) or represented by a meaningless filename. When that image is a linked icon or navigation element, the failure doesn't just make content inaccessible — it makes the page unusable. Alt text is not a description of appearance; it is a description of meaning and function.

Despite being the most widely understood accessibility principle, it's among the most violated: the WebAIM Million 2025 report found alt text missing on 55.5% of pages, making it the second most prevalent accessibility failure after low-contrast text.

The impact is direct and severe. For blind and low-vision users on screen readers, an image without alt text is either silent — invisible — or read out as a meaningless filename. When that image is a linked icon or navigation element, the failure doesn't just hide content; it makes the page unusable. The key insight is that alt text describes meaning and function, not appearance.

Alternative text is the foundational requirement of web accessibility: WCAG Success Criterion 1.1.1, at Level A, the minimum standard. It states that every image, icon, or non-text element that conveys meaning must have a text alternative communicating the same information to users who can't see it.

Despite being the most widely understood accessibility principle, it's also one of the most violated — the WebAIM Million 2025 report found alt text missing on 55.5% of pages, the second most prevalent failure after low-contrast text. The impact is direct: for screen-reader users, an image without alt text is either silent or announced as a meaningless filename, and when that image is a linked icon or navigation element, the page can become unusable.

The crucial principle is what alt text is for. It's not a description of appearance but a description of meaning and function — what the image communicates, or what it does, rather than what it looks like. A decorative image needs empty alt text so screen readers skip it; a functional one needs alt text conveying its purpose. It connects to the POUR principles and accessibility broadly.

Alt text is partly automatable and partly not, and Kweri is honest about the split. Its automated checks can reliably detect images that have *no* alt attribute at all — a common and serious failure — and flag them. What automated testing fundamentally cannot judge is whether existing alt text is *good*: whether it conveys the image's actual meaning and function, or is a useless filename, an appearance description, or simply wrong. That's a human judgement. So Kweri catches missing alt text mechanically and prompts you to ensure the alt text that exists is meaningful, which only a person can verify.

Identified by W3C Web Accessibility Initiative (WAI). Catalogued from W3C — Understanding SC 1.1.1: Non-text Content.

Based on WCAG SC 1.1.1 (Level A); the linked W3C page is the primary source.

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