WCAG font size: what the guidelines require and what they do not

People search for a "WCAG minimum font size" because it feels like there should be one. There is no minimum font size in WCAG 2.0, 2.1 or 2.2. None of the success criteria says "body text must be at least 16 pixels". What WCAG does require is that people can make text bigger, that the layout survives it, and that small text has enough contrast. This page sorts out the four criteria that matter and, clearly separated, the recommendations we give on top.

This is general information, not legal advice.

The short answer

1.4.4 Resize Text: 200% without loss

Text, except captions and images of text, can be resized up to 200% without assistive technology and without loss of content or functionality. In practice, test with the browser zoom (Ctrl/Cmd and +) or with the browser's text-size setting:

• no text is cut off or overlaps other text;
• buttons, menus and form fields still work;
• nothing important disappears behind a fixed header.

Typical failures: text in boxes with a fixed height, font-size locked with vw units only, and a maximum-scale=1 or user-scalable=no in the viewport meta tag that stops people from zooming on a phone.

1.4.10 Reflow: 320 CSS pixels

Content must be readable at a width of 320 CSS pixels — the same as zooming a 1280 pixel wide window to 400% — without scrolling in two directions. Long text should wrap; the page should not need horizontal scrolling to read a line. Exceptions exist for content that needs a two-dimensional layout, such as maps, data tables and complex diagrams.

1.4.12 Text Spacing

People with low vision or dyslexia often override spacing with a browser extension or a user style sheet. WCAG asks that nothing is lost when they set:

• line height to at least 1.5 times the font size;
• spacing after paragraphs to at least 2 times the font size;
• letter spacing to at least 0.12 times the font size;
• word spacing to at least 0.16 times the font size.

You do not have to use these values in your design. Your design only has to keep working when someone applies them. The usual failures are fixed heights on buttons and cards, and text that is clipped with overflow: hidden.

1.4.3 and the definition of large text

The only place where a font size appears in a level AA criterion is the definition of large scale text, used by the contrast rule:

• Large text: at least 18 point (24 CSS pixels) in regular weight, or at least 14 point bold (about 18.66 CSS pixels).
• Large text needs a contrast ratio of at least 3:1; all other text needs 4.5:1.
• At level AAA (1.4.6), the values are 7:1 and 4.5:1.

So size changes the contrast you need, not whether the text is allowed. A thin grey 13px price label is the classic shop failure: small, light and low in contrast at the same time. Test colour pairs with our contrast checker.

Related criteria

• 1.4.5 Images of Text (AA): use real text instead of text baked into images, so it can be zoomed, recoloured and read aloud. Banners with sale text in the image are a common failure.
• 1.4.8 Visual Presentation (AAA): asks, among other things, for blocks of text no wider than 80 characters and text that can be resized to 200% without horizontal scrolling. It is AAA and not required by laws, but useful as guidance for long text.
• 2.5.8 Target Size (AA): not about text, but small text links in a menu often also fail the 24 by 24 pixel target size.

Justified, centred and bold text, fonts and line length

These questions come up often. Most of the answers sit in one level AAA criterion, 1.4.8 Visual Presentation. AAA is not required by laws or by a level AA claim, so treat everything from 1.4.8 below as a recommendation.

Justified text

1.4.8 asks that a mechanism is available so that blocks of text are not justified (aligned to both the left and the right margin). The W3C explains why: justification stretches word spacing unevenly and can create "rivers of white" running down the page, which makes reading hard, and sometimes impossible, for some people with cognitive disabilities. At level AA, justified text is not a failure. Our recommendation: align body text to the left (or to the right in right-to-left languages), especially on narrow screens, where justification produces the largest gaps.

Line length

1.4.8 also asks that the width of blocks of text can be limited to no more than 80 characters or glyphs (40 for Chinese, Japanese and Korean). The same criterion asks for line spacing of at least space-and-a-half within paragraphs, paragraph spacing at least 1.5 times larger than the line spacing, user-selectable foreground and background colours, and text that can be resized to 200% without horizontal scrolling on a full-screen window. The mechanism can be provided by the browser; the page does not have to build its own controls.

Centred text

No WCAG criterion mentions centred text. Our recommendation: centre short headings and buttons if you like, but keep paragraphs, lists and form labels left-aligned. Long centred text has a ragged left edge, so readers must search for the start of every line, which is harder at 200% zoom and for people with dyslexia.

Bold text

Bold appears in WCAG in two places:

• Large text: 14 point bold (about 18.66 CSS pixels) already counts as large text and needs only 3:1 contrast at AA instead of 4.5:1 (1.4.3).
• Meaning: if bold or another text style carries meaning — "fields in bold are required", a bold word marking a warning — that meaning must also be available in markup or text. W3C lists using changes in text presentation to convey information without the appropriate markup or text as failure F2 of 1.3.1 Info and Relationships. Use <strong> or <em> for emphasis, and say "required" in words.

WCAG does not limit how much bold you use. Long passages in bold are harder to scan; reserve it for emphasis.

"Normal" text size

WCAG does not define "normal text". It defines large scale text, and everything smaller is what checkers call normal text: anything below 18 point (24 CSS pixels) in regular weight or below 14 point bold. Normal text needs a contrast ratio of at least 4.5:1 at AA, large text 3:1. There is still no minimum size for normal text; see the table at the top.

Fonts and font checkers

WCAG does not name or ban any font, and it sets no font family requirement. What matters is that your font works with the criteria above: it can be zoomed to 200%, keeps working when spacing is increased (1.4.12), and has enough contrast at its weight — thin fonts can look fainter than their colour suggests, which W3C notes in Understanding 1.4.3. Our recommendation: choose a family with clearly distinct characters (I, l and 1; O and 0), a regular weight that is not hairline-thin, and full support for the languages of your site.

A "WCAG font checker" cannot approve a font, because there is no list of allowed fonts. What an automated check can do — and what our WCAG checker does — is test the contrast of every text against the large-text rule and flag a viewport that blocks zooming. Line length, justification and how text behaves at 200% need a look by a person.

Recommendations, not requirements

The following values are our recommendations for readable shop and service sites. They are not WCAG requirements, and a page does not fail WCAG for using other values.

• Body text around 16 px. That is the default text size of common browsers. Going much smaller for body text makes the 200% zoom do more work.
• Use relative units (rem, em) for font sizes and line heights so the text size people set in their browser is respected.
• Line height of 1.4–1.6 for body text and line length of roughly 50–80 characters.
• Avoid fixed heights on elements that contain text; let them grow.
• Do not block zoom in the viewport meta tag.
• Small print with care. Legal notes, prices per unit and form hints are read by everyone, so give them the same contrast as body text.

How to check font size and zoom problems

1. Automated check. Our free WCAG checker finds low contrast, including the large text rule, and a viewport that blocks zooming. It cannot judge whether a zoomed layout still works.
2. Zoom to 200%. Use the browser zoom and walk through home, product, cart and checkout.
3. Narrow window or 400% zoom. Check that text wraps and nothing needs horizontal scrolling.
4. Text spacing. Apply the 1.4.12 values with a bookmarklet or with the text spacing tool of our browser extension and look for clipped text.

The full routine is in how to test WCAG. Our checks are an automated check, not a full audit, and not legal advice.

Frequently asked questions

What is the minimum font size in WCAG?

There is none. No WCAG 2.0, 2.1 or 2.2 success criterion sets a minimum font size. WCAG asks instead that text can be enlarged to 200% (1.4.4), reflows on a narrow screen (1.4.10), survives larger spacing (1.4.12) and has enough contrast (1.4.3).

What font size counts as large text in WCAG?

At least 18 point, which is 24 CSS pixels, in regular weight, or at least 14 point bold, about 18.66 CSS pixels. Large text needs a contrast ratio of 3:1 at level AA instead of 4.5:1.

Is 16px required by WCAG?

No. 16 pixels is the default text size of common browsers and a sensible recommendation for body text, but WCAG does not require it. A 16px text that cannot be zoomed fails, a smaller text that zooms well can pass.

Which zoom level does WCAG require?

Text must be resizable up to 200% without loss of content or functionality (1.4.4). Content must also reflow at a width of 320 CSS pixels, which equals 400% zoom on a 1280 pixel wide window, without scrolling in two directions (1.4.10).

Should I use px, em or rem for font sizes?

WCAG does not prescribe units. Relative units such as rem and em make it easier to respect the text size people set in their browser, which is why we recommend them, but px is not a failure on its own.

Does WCAG allow justified text?

At level AA, yes. Only the AAA criterion 1.4.8 Visual Presentation asks that a mechanism is available so blocks of text are not justified, because uneven word spacing creates rivers of white space. AAA is a recommendation, not a legal requirement.

Sources

• W3C, WCAG 2.2 (1.4.3, 1.4.4, 1.4.10, 1.4.12 and the definition of large scale text): https://www.w3.org/TR/WCAG22/
• W3C, Understanding 1.4.4 Resize Text: https://www.w3.org/WAI/WCAG22/Understanding/resize-text.html
• W3C, Understanding 1.4.10 Reflow: https://www.w3.org/WAI/WCAG22/Understanding/reflow.html
• W3C, Understanding 1.4.8 Visual Presentation: https://www.w3.org/WAI/WCAG22/Understanding/visual-presentation.html
• W3C, Understanding 1.3.1 Info and Relationships: https://www.w3.org/WAI/WCAG22/Understanding/info-and-relationships.html
• W3C, Understanding 1.4.3 Contrast (Minimum): https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html