The Free WCAG Text Spacing Checkers Worth Using in 2026

If you run Lighthouse or axe on your site expecting a WCAG 1.4.12 pass/fail, you will not get one. The automated accessibility scanners all catch color contrast, alt text, heading order, and ARIA bugs — but WCAG 1.4.12 text spacing is largely a manual test. Here is what the major free tools actually check, where they fall short, and how dedicated spacing checkers fill the gap.

What the major free accessibility tools actually check

Tool	Color contrast	Heading order	Alt text	Text spacing (1.4.12)
axe DevTools	✓	✓	✓	Partial — font-size only
Lighthouse	✓	✓	✓	No
WAVE	✓	✓	✓	No
Microsoft Accessibility Insights	✓	✓	✓	No
Siteimprove	✓	✓	✓	Partial
Browser dev tools (manual override)	N/A	N/A	N/A	Full (manual test)
WildandFree Spacing Checker	No	No	No	Full (paste CSS values)

Automated scanners are great at "does the page have a problem" but struggle with "does the page survive an override" — which is what 1.4.12 tests.

Why WCAG 1.4.12 is hard to automate

The rule is not "your CSS has line-height 1.5" — it is "when users force line-height 1.5, your layout does not break." An automated tool can verify the declared values, but checking whether your layout survives an override requires rendering the page with new CSS and measuring if content overlaps or clips.

Some enterprise tools (Deque axe Pro, Siteimprove, Tenon) do attempt this via headless browser rendering, but they are expensive and not free. For free tools, the 1.4.12 gap remains.

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The manual testing workflow (still necessary)

1. Run Lighthouse/axe for the automated wins.
2. Open dev tools, go to Sources, create a snippet.
3. Paste the WCAG 1.4.12 override CSS:

const style = document.createElement('style');
style.textContent = `
  * {
    line-height: 1.5 !important;
    letter-spacing: 0.12em !important;
    word-spacing: 0.16em !important;
  }
  p { margin-bottom: 2em !important; }
`;
document.head.appendChild(style);

4. Run the snippet. Scroll every page. Look for clipped text, overlapping content, horizontal scroll.
5. Fix layout bugs as you find them.

This catches the layout-resilience half. Use our spacing checker for the declared-values half.

Which tools to run and when

• axe DevTools (browser extension): daily work, quick scans during development. Best for catching recently-introduced regressions.
• Lighthouse: CI/CD pipeline checks. Integrates with build systems.
• WAVE browser extension: great visual overlay. Good for training new developers on accessibility.
• Dev tools + manual override: WCAG 1.4.12 layout testing. Required — no free tool replaces this.
• Dedicated spacing checker: design-time decisions about what CSS values to use.

Enterprise tools that do cover 1.4.12

For full 1.4.12 automation, look at:

• Deque axe Pro — adds layout-resilience testing on top of axe DevTools.
• Siteimprove — enterprise accessibility scanning with 1.4.12 coverage.
• Tenon.io — API-first accessibility scanner with broad WCAG 2.2 coverage.
• BrowserStack Accessibility Testing — integrated with existing test workflows.

All paid, starting around $100/month. For smaller teams, manual testing with dev tools plus a free spacing checker gets you 95% of the way for no cost.

Frequently Asked Questions

Will Lighthouse give me a 100 accessibility score if I ignore 1.4.12?

Yes — Lighthouse does not check 1.4.12 at all. You can score 100 and still fail the criterion. Automated score is not the same as actual compliance.

Does axe DevTools cover all WCAG AA rules?

No. axe covers roughly 50-60% of AA automatically. The remaining 40-50% — including 1.4.12, 1.4.13, much of 2.4 and 3.3 — requires manual testing.

Is there an axe rule for text spacing?

axe has a rule for "text must have sufficient color contrast" and "text should not overflow" but no dedicated rule checking 1.4.12's four spacing values. The gap is consistent across free tools.

What about browser extensions like ANDI or Accessibility Insights?

Both good for their specific focuses (ANDI for ARIA, Accessibility Insights for tab order and visuals) but neither tests 1.4.12 text spacing override resilience.