Accessible Data Visualisation

Charts and visualisations should remain understandable — important information must not rely entirely on visuals.

01 — Purpose

Data beyond the chart

Charts and visualisations should remain understandable — important information should never rely entirely on visuals alone.

Bar heights, line trends, and colour segments carry meaning for sighted users. Screen reader users, colour-blind users, and people on small screens need the same insights in text, tables, or structured summaries.

See the data visualisation pattern and colour and contrast systems.

02 — Principles

Understandable beyond the chart

Data should remain understandable beyond the chart itself.

  • text alternatives — summary of trend, key values, and takeaway
  • accessible colour usage — not colour-only series distinction
  • clear labelling — axes, units, legends, and chart title
  • table fallbacks where appropriate — same data in sortable HTML table

03 — Practice

Good accessible visualisation

Support screen readers, keyboard interaction, and low-vision users.

  • provide a visible data table or “view as table” toggle — especially for dashboards
  • describe the chart with aria-label or linked visible summary text
  • pair colour with patterns, labels, or markers — see colour and contrast
  • make tooltips and drill-down keyboard-operable — not hover-only
  • avoid motion-only emphasis — respect reduced motion

04 — Avoid

Visualisation barriers

Unreadable charts exclude users from decisions.

  • colour-only meaning — red/green lines with no labels or patterns
  • unreadable charts — tiny text, low contrast, unlabelled axes
  • inaccessible interaction — canvas/SVG with no keyboard or AT support
  • image-only charts with no textual equivalent
  • critical KPIs only in graphics — no plain-language number nearby

05 — Close

Ask what a non-sighted user learns

If the answer is “nothing,” the visualisation is decorative or broken.

Review dashboards with screen reader and keyboard only. Can users get the headline number and trend without seeing the chart? If not, add summary text or a data table.

See data visualisation, dashboard patterns, and accessibility QA checklist.