---
name: Chart description
slug: chart-description
category: accessibility
status: published
created: 2026-08-21T00:00:00.000Z
modified: 2026-08-21T00:00:00.000Z
definition: "The text alternative for a chart: a summary of the takeaway plus
  access to the underlying values, not a recital of the pixels."
aliases:
  - name: chart alt text
  - name: accessible chart
  - name: data table fallback
tags:
  - assistive-tech
  - content-design
  - dataviz
relations:
  contrastWith:
    - alt-text
    - long-description
    - sonification
  variantOf: []
  partOf: []
  seeAlso:
    - chart
    - data-table
implementations: []
sources:
  - title: "W3C WAI: Complex images"
    url: https://www.w3.org/WAI/tutorials/images/complex/
  - title: "Apple HIG: Charts"
    url: https://developer.apple.com/design/human-interface-guidelines/charts
demo: inline
exhibit: false
useWhen: a chart needs to work for readers who cannot see it
---

A [chart](/chart) carries two separate things a text alternative has to deliver, and most
alternatives deliver neither. The first is the conclusion the chart was drawn to support.
The second is the numbers that support it. The shape that works is a one line summary
naming the takeaway ("support tickets fell by a third after the March release") followed by
real access to the values, normally a [data table](/data-table) sitting beside the figure or
behind a disclosure, marked up as rows and columns a [screen reader](/screen-reader) can
walk. The W3C's complex images tutorial calls this pairing a short description plus a long
description, and it is the only arrangement that survives a chart with more than one series.

[Alt text](/alt-text) is the shorter word for the shorter job, and the two are worth keeping
apart. Alt text is the string an image carries, and for a chart it can hold the summary half
at best, which is why a chart description usually cannot live in an attribute at all. Going
the other way: writing `alt="bar chart of quarterly revenue"` describes the picture, and
describing the picture is exactly what a chart alternative must not do, because a reader who
cannot see it did not ask for the pixels to be recited. Say what the chart shows, then hand
over the numbers. [Audio description](/audio-description) sounds like a relative and is not
one: that narrates a moving picture in the gaps of its own soundtrack, while a chart
description is static text that the reader controls the pace of.

None of the chart's own furniture carries across the boundary by itself. An
[axis](/axis) is a ruled edge with tick labels a reader can see, a
[chart legend](/chart-legend) is a colour key nobody can hear, and
[direct labeling](/direct-labeling) puts names next to lines that are also unavailable. A
[chart annotation](/chart-annotation) is the exception worth exploiting: the note already
pinned onto the data, saying what to see, is usually the best first draft of the summary
line, because somebody has already done the work of deciding what the chart is for.

The practical test is to read the alternative aloud with the chart covered. If the listener
cannot repeat the takeaway, the summary is missing. If they cannot answer a question about a
specific point, the values are missing. A description that passes both is worth building
into the page for everyone: sighted readers use the table too, and a
[sparkline](/sparkline) or a small multiple with a table under it is a better artefact than
either half alone.