Success Criteria

WCAG 1.4.12 Text Spacing

Success Criterion 1.4.12 requires that no loss of content or functionality occurs when a user applies more generous text-spacing values: line height to at least 1.5× font size, paragraph spacing to at least 2× font size, letter spacing to at least 0.12× font size, and word spacing to at least 0.16× font size. It's a Level AA criterion under Guideline 1.4 (Distinguishable), added in WCAG 2.1.

Who benefits from increased spacing

People with dyslexia and certain other reading or low-vision conditions often find text significantly more readable with looser spacing — dense, tightly-packed text can cause words to visually blend together or lines to be hard to track. Browser extensions and assistive tools exist specifically to override a page's spacing to these more generous values; this criterion requires that a page doesn't break when that override is applied.

What "doesn't break" means concretely

When spacing is increased, text shouldn't get clipped by a fixed-height container, overlap with other elements, or cause content to become unreadable or inaccessible. A component built with a hardcoded, too-small height for its text will overflow or clip once line-height increases — that's the most common way this criterion fails.

How to actually test it

Apply a bookmarklet or browser extension that sets the required spacing values (several free ones exist specifically built for testing 1.4.12), or override the CSS yourself in DevTools with the exact ratios above, then check whether any text gets cut off, overlaps, or becomes impossible to read.

The underlying design principle

The practical fix is the same discipline that satisfies Reflow (1.4.10) and Resize Text (1.4.4): avoid fixed-height containers for text content, let containers grow to fit their content rather than clipping or hiding overflow. A component library built with flexible, content-driven sizing rather than hardcoded pixel heights tends to pass this criterion without any dedicated extra work.

Common questions

What is WCAG 1.4.12 Text Spacing?

A Level AA criterion: content must remain readable and functional when users increase line, paragraph, letter, and word spacing to specified values.

Why do users change text spacing?

People with dyslexia and low vision often increase spacing to read more easily; the page must not break or clip text when they do.

What causes 1.4.12 violations?

Fixed-height containers or overflow:hidden that clip text when spacing increases, or elements that overlap once lines grow taller.