Goal
Ensure users can adjust text spacing for readability without breaking content.
Success Criterion · WCAG 1.4.12
Text Spacing
In content implemented using markup languages that support text style properties, no loss of content or functionality occurs by setting line height to at least 1.5 times the font size, spacing following paragraphs to at least 2 times the font size, letter spacing to at least 0.12 times the font size, and word spacing to at least 0.16 times the font size.
Level AAWCAG 2.1Perceivable1.4 · Distinguishable
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What to do
Support user overrides for line height, paragraph spacing, letter spacing, and word spacing without losing content or functionality.
Why it matters
Users with dyslexia and low vision often increase spacing; layouts that clip or overlap can become unusable.
Success criterion
What WCAG 1.4.12 requires
Summarized directly from the official Understanding document so teams can quote the requirement accurately.
In content implemented using markup languages that support the following text style properties, no loss of content or functionality occurs by setting all of the following and by changing no other style property: Line height (line spacing) to at least 1.5 times the font size; Spacing following paragraphs to at least 2 times the font size; Letter spacing (tracking) to at least 0.12 times the font size; Word spacing to at least 0.16 times the font size.
Intent
Why WCAG created this requirement
- Text spacing adjustments improve readability for many users.
- Content must remain usable when users apply spacing via extensions or user stylesheets.
- The requirement is “no loss of content or functionality,” not pixel-perfect layout.
Benefits
Who gains when you pass
- Users with dyslexia can reduce crowding and improve reading accuracy.
- Low vision users can improve legibility and tracking.
- Users with cognitive disabilities can better parse text blocks.
- All users can personalize reading comfort without breaking the UI.
Why it matters
User impact when this criterion fails
Summaries drawn from the Understanding document help you socialize impact statements with product stakeholders.
Text may overlap or be clipped when spacing is increased.
Buttons/inputs may become unusable if labels overlap controls.
Hidden overflow may cut off important content and instructions.
Overview
Users must be able to apply increased text spacing (line height, paragraph spacing, letter and word spacing) without content overlapping, being cut off, or losing functionality. This supports readability customizations commonly used by people with dyslexia and low vision.
- Avoid fixed-height containers for text and controls.
- Avoid `overflow: hidden` on text containers unless necessary; ensure it doesn’t hide content.
- Allow wrapping and expansion for labels, headings, and buttons.
- Test with a text spacing bookmarklet/extension applying the specified values.
Reference: All summaries and highlights originate from Understanding WCAG 1.4.12 and the W3C quick reference.
Fast facts
- Conformance level
- Level AA
- WCAG version introduced
- WCAG 2.1
- Principle
- Perceivable
- Guideline
- 1.4 · Distinguishable
Examples
Make success tangible for teams
Share pass/fail snapshots to coach designers, engineers, QA, and content authors.
Navigation
Pass
Nav items wrap or stack when spacing increases; menu remains usable.
Fail
Nav uses fixed height and overflow hidden, cutting off text when spacing increases.
Form errors
Pass
Error messages wrap and remain visible with increased spacing.
Fail
Error messages overlap inputs or are clipped by container height.
Buttons
Pass
Buttons expand vertically and wrap label text if needed.
Fail
Buttons clip text because of fixed height and no wrapping.
Evidence to keep
Document conformance decisions
Capture artifacts for VPATs, procurement reviews, and regression testing.
- Document “no fixed heights” guidelines for components that contain text.
- Include spacing-adjustment testing in accessibility QA checklists.
- Capture before/after screenshots for key templates under spacing adjustments.
Official resources
Deep dives and supporting material
Keep these links handy when writing acceptance criteria or responding to audits.
Understanding 1.4.12
Official W3C interpretation, techniques, and intent for Text Spacing.
Quick Reference 1.4.12
Filterable list of sufficient techniques and failures.
Technique C35
Allowing for text spacing without loss of content or functionality.
Failure F104
Failure due to clipping or overlapping text when spacing is adjusted.
Implementation checklist
Capture progress and blockers
- Use flexible layouts that can grow vertically with text.
- Avoid fixed heights for headings, buttons, and form labels.
- Ensure line wrapping is allowed for text blocks and labels.
- Avoid clipping content with overflow hidden on containers with text.
- Test key templates with increased spacing values.
- Fix components that break under spacing adjustments (e.g., pill buttons, tight nav).
Testing ideas
Prove conformance with evidence
- Apply text spacing settings: line-height 1.5, paragraph spacing 2, letter spacing 0.12em, word spacing 0.16em.
- Verify no content is cut off or overlaps in key pages and components.
- Verify interactions still work (menus, modals, form submission).
- Check that focus indicators and clickable targets remain usable.
- Test in both light and dark themes and at zoom levels.
Related success criteria
More from Distinguishable (1.4)
WCAG 1.4.1Use of ColorLevel AWCAG 1.4.2Audio ControlLevel AWCAG 1.4.3Contrast (Minimum)Level AAWCAG 1.4.4Resize TextLevel AAWCAG 1.4.5Images of TextLevel AAWCAG 1.4.6Contrast (Enhanced)Level AAAWCAG 1.4.7Low or No Background AudioLevel AAAWCAG 1.4.8Visual PresentationLevel AAAWCAG 1.4.9Images of Text (No Exception)Level AAAWCAG 1.4.10ReflowLevel AAWCAG 1.4.11Non-text ContrastLevel AAWCAG 1.4.13Content on Hover or FocusLevel AA