meta-viewport
Web validation
<meta name="viewport" /> element must not block user zoom by including user-scalable=no or a maximum-scale below 2.People with low vision often enlarge pages to read comfortably.
Disabling browser or pinch-zoom in the viewport meta tag prevents text from reaching the 200% enlargement required by WCAG 1.4.4. Keep zoom available by omitting restrictive properties or allowing larger maximum-scale values.
Note: The <meta name="viewport" /> tag is specifically designed for mobile browsers to control how websites are scaled and rendered on smaller screens. In most cases it is ignored by desktop browsers.
Pass Patterns
The <meta name="viewport" /> does not set scaling limits
The snippet below allows full browser and pinch-zoom because it sets no scaling limits.
<meta name="viewport" content="width=device-width, initial-scale=1">Fail Patterns
Scaling the screen by the user is disabled
This example fails because user-scalable is set to no, completely disabling zoom.
<meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no">Maximum scale is limited
Limiting maximum-scale to 1 likewise prevents users from enlarging content and fails.
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1">ACT Rules
Try It Yourself
Using a browser on a mobile device
- Open the page in a browser on a mobile device.
- Pinch-zoom the content to increase its size.
Expected result: The page content size scales up.
Actual result: The page is not zoomed in, and the content stays at the same size.
Inspecting the browser dev-tools
- Open the page in a modern browser, and open the browser DevTools on the Elements panel.
- Within the document’s
<head>element locate the<meta name="viewport" />tag.
Expected result: The <meta name="viewport" /> content value does not include user-scalable=no or a maximum-scale below 2.
Actual result: The <meta name="viewport" /> content value includes user-scalable=no and/or a maximum-scale below 2.
FAQ
How does this issue relate to 1.4.4 Resize Text?
SC 1.4.4 requires that users can enlarge text up to 200% without assistive technology. Blocking browser zoom violates this requirement because it removes a primary mechanism for resizing content.
Why is this issue marked as Critical?
Preventing zoom disproportionately affects people with low vision and users on small screens. Because it removes a built-in accessibility feature across all major browsers, the impact is widespread, immediate, and severe, justifying a Critical severity level.
Standards and Regulations
| Standard | Success Criterion | Reference |
|---|---|---|
| WCAG 2.2 | 1.4.4 Resize text (AA) | Except for captions and images of text, text can be resized without assistive technology up to 200 percent without loss of content or functionality. |
| EN 301 549 | 9.1.4.4 Resize text | Same as the WCAG text. |
| 508 Trusted Tester | 1.4.4-resize-text, 18.A | There is a mechanism to resize, scale, or zoom in on the text to at least 200% of its original size without loss of content or functionality. |