Perceivable
Use sufficient contrast, readable type, and redundant signals so the message does not depend on hue or tiny labels.
Free chart accessibility checker
Check whether your chart communicates beyond color alone.
Test text and graphical contrast, then run through titles, labels, non-color cues, alt text, data alternatives, and source visibility. A practical preflight for newsletters, research, reports, slides, and social graphics.
1. Check the chart palette
Test text at 4.5:1 and essential graphical colors at 3:1 against the background.
75
Accessibility preflight
Needs a few fixes
This checks key contrast and editorial signals. It is not a complete WCAG conformance audit.
Text contrast
18.33:1
Passes 4.5:1
Graphical contrast
Pass
All series reach 3:1
Color results
Series 1
6.52:1Series 2
5.33:1Series 3
6.37:1Next fixes
- Use labels, markers, patterns, or line styles so color is not the only signal.
- Add concise alt text or a longer chart description.
- Provide the underlying data as a table or download where practical.
Accessible chart basics
Contrast is one layer, not the whole answer.
Understandable
State the subject and takeaway, define units, label series directly, and avoid a visual encoding that misrepresents the data.
Available another way
Provide alt text or a longer description and give readers a table or data download for exact values where practical.
Use the full accessible-chart workflow
The complete guide covers contrast, color vision, typography, labels, alt text, data tables, mobile exports, testing, and an editorial checklist.
Practical answers before publishing.
What contrast ratio should chart text use?
Normal-size text should generally reach at least 4.5:1 against its background. Large text can use 3:1 under WCAG’s size and weight definitions. This tool applies the more conservative 4.5:1 check.
What contrast ratio should chart lines and bars use?
Essential graphical objects and states generally need 3:1 against adjacent colors. Not every decorative mark is required to meet this threshold, so review whether the element is necessary to understand the chart.
Is color contrast enough to make a chart accessible?
No. Use direct labels, markers, patterns, line styles, or text so color is not the only signal. Provide alt text or a longer description and make the underlying data available where practical.
What should chart alt text include?
Identify the chart type and subject, then summarize the main pattern, comparison, or outlier. Avoid repeating every value when a data table or longer description is available.
Does a chart need a data table?
A table or downloadable dataset gives readers access to exact values and can provide a stronger alternative for complex charts. The appropriate implementation depends on the publishing surface.
Does a high score mean my chart is WCAG compliant?
No. This is a focused preflight, not a conformance audit. Complete accessibility also depends on semantic structure, keyboard behavior, screen-reader output, zoom, motion, context, and real-user testing.