ARIA label

Key differences between aria-label, alt text, and labels

aria-label/aria-labelledby supply an accessible name for most roles and elements, especially links, buttons, and custom widgets. The HTML alt attribute is specific to img (and area) and provides the image’s alternative text; it is the normative mechanism for naming native images. The label element (or for/id pairing) associates visible text with form controls and also contributes the accessible name.

For native img elements, alt is the conforming source of the accessible name; aria-label is not a substitute in HTML conformance. For elements given role="img" (for example, an SVG icon wrapped in a span), aria-label or aria-labelledby can provide the name.

Overview

Accessible name computation determines an element’s name from author-supplied attributes (aria-label, aria-labelledby), associated labels, and, where applicable, text content. When an ARIA label is present, it generally takes precedence over text content as the element’s name (“name from author”).

The exposed name affects how controls are announced in reading and focus modes, how elements appear in accessibility trees, and how voice commands target them. It does not, by itself, affect layout, rendering, or network performance.

Scope relative to SEO signals

ARIA labels are accessibility metadata consumed by assistive technologies and accessibility APIs; they are not primary SEO signals. Search systems primarily rely on visible text, structural semantics, and dedicated attributes like alt for images.

For links and buttons, anchor text comes from visible text content; aria-label is not consistently treated as anchor text by crawlers. Consequently, ARIA labelling improves accessibility but does not replace visible, meaningful text for indexing or ranking.

Governing specifications

Relevant standards include WAI-ARIA (roles, states, and properties), ARIA in HTML (conformance rules for using ARIA with HTML), and the Accessible Name and Description Computation specification (how names are derived). Platform mappings are defined in the HTML Accessibility API Mappings (HTML AAM) and Core AAM, and WCAG 2.x sets success criteria requiring controls and images to have appropriate names.