Success Criterion 1.4.1
Conformance level A

1.4.1 · Use of Color

Lesson overview · Use of Color

In plain language

Color must never be the only way information is shown (errors, links, statuses, chart series).

Who it affects

People with color-vision deficiency, low vision, or constrained viewing conditions such as strong glare.

How to check

View the page in grayscale: can you still spot links, errors, required fields, selected items, and chart differences?

Common misconception

Removing color entirely isn't the fix. The rule only requires that color not be the *only* way information is shown, a second cue like an icon or label alongside the color is enough.

Learn more

Understanding Understanding this success criterion (opens in a new tab)

Scenarios in this lesson

Chart Legend Colors Never Explained in the Image’s Alt Text
In-Text Links Distinguishable From Body Text Only by Color
Required or Error Fields Marked Only by a Red Border
Chart Data Series Told Apart Only by Line or Bar Color
Online/Offline Status Shown Only as a Colored Dot
Form Validation That Turns Borders Red as the Only Cue
Calendar Availability Shown Only Through Colored Cells
Selected Tab or Toggle Marked Only by a Color Change
Added and Removed Content Shown Only via Background Color
Editable Fields Identified Only by a Color-Coded Legend
Heatmap With No Value Labels or Data Table Alternative
Link Color That Only Changes on Mouse Hover
Wizard Progress Steps Distinguished Only by Color
Highlighted Text Meant to Signal Importance by Color Alone