WCAG 1.3.3: How to Fix Sensory Characteristics Failures

Last updated: 2026-03-22

Level A Perceivable WCAG 1.3.3

What This Criterion Requires

WCAG 1.3.3 requires that instructions for understanding and operating content do not rely solely on sensory characteristics of components such as shape, color, size, visual location, or orientation. When instructions reference interface elements, they must include information that can be understood without relying on a single sense. For example, telling users to 'click the round green button' relies on both shape and color, which are inaccessible to blind users and users with color vision deficiency. Instead, instructions should include text labels, names, or other non-sensory identifiers such as 'click the Submit button.' Similarly, saying 'the options on the right side of the page' relies on visual location, which is meaningless to screen reader users who perceive content linearly. Instructions may include sensory references as supplementary information, but there must always be a non-sensory way to identify the referenced element. This criterion applies to all instructions within content, including error messages, help text, tutorials, and inline guidance.

Why It Matters

Users who are blind cannot perceive shape, color, size, or visual location. When instructions depend solely on these visual characteristics, blind users and screen reader users cannot follow them. Users with color vision deficiency cannot distinguish elements identified only by color. Users on small screens or using screen magnification may not be able to perceive the relative location of elements described as being 'to the left' or 'at the top of the page.' Users with cognitive disabilities may struggle to identify elements based on abstract sensory descriptions rather than explicit labels. By ensuring instructions include non-sensory identifiers like text labels, everyone can locate and interact with the referenced elements regardless of their abilities or the device they are using. This is a fundamental principle of inclusive design: information should never be conveyed through a single sensory channel alone.

Common Failures and How to Fix Them

Instructions that rely solely on visual location

Help text directs users to an element using only its visual position on the page. Screen reader users, users on mobile devices with different layouts, and users with screen magnification cannot reliably locate elements by visual position alone.

Inaccessible 
<p>To save your progress, use the button on the right side of the page.</p>
<div class="actions">
  <button class="left">Cancel</button>
  <button class="right">Save</button>
</div>
Accessible 
<p>To save your progress, click the "Save" button below.</p>
<div class="actions">
  <button>Cancel</button>
  <button>Save</button>
</div>

Error identification using only color

Form validation highlights fields with errors only by changing the border color to red, without any text label or icon to indicate which fields have errors. Users who cannot see color have no way to identify the problematic fields.

Inaccessible 
<style>
  .error { border-color: red; }
</style>
<p>Please fix the errors highlighted in red.</p>
<input type="email" class="error" value="invalid-email">
Accessible 
<style>
  .error { border-color: #d32f2f; }
</style>
<p>Please fix the errors listed below:</p>
<div class="error-message" role="alert">
  <p>Email: Please enter a valid email address.</p>
</div>
<label for="email">Email</label>
<input type="email" id="email" class="error" aria-describedby="email-error" value="invalid-email">
<span id="email-error" class="error-text">Please enter a valid email address.</span>

How to Test

  1. Review all instructional text on the page and check that references to interface elements include text-based identifiers (labels, names) rather than relying solely on shape, color, size, or visual position.
  2. Use a screen reader to encounter the instructions and verify that you can identify the referenced element without visual information.
  3. Test the page with a grayscale filter applied (browser extension or OS setting) to verify that color is not the only means of conveying information in instructions.
  4. Check error messages, help text, tooltips, and onboarding instructions for references that rely on sensory characteristics alone.

CMS-Specific Guidance

This criterion commonly causes issues on these platforms:

Further Reading

Related WCAG Criteria