How do I describe a chart without restating every plotted value?

Give readers an orientation, not a verbal copy of every mark. In a few sentences, say what the chart is about, how it is organized, and the most important feature that is visibly supported. For example: what groups are compared, what the axes or categories represent, and whether one group stands out or values cluster within a range.

A useful plan has two layers: a short identification and overview, followed by access to fuller detail when the chart contains substantial information. W3C’s WAI guidance describes this two-part approach for complex images; its chart example includes scales, values, relationships, and trends, and notes that visual composition may also matter. It also recommends referring to and summarizing complex images in accompanying text. [S1]

That does not mean every chart needs a long description or that an overview can replace exact data. Decide what someone needs to understand the point, then provide a table or fuller description if exact values or relationships matter.

First identify the chart’s apparent purpose from its title, labels, legend, and the surrounding text. Then inspect the plotted information and choose a feature that helps answer that purpose: a clear comparison, an unusually high or low category, a visible grouping, or a relationship that the data actually supports.

Keep the wording at the same level of certainty as the picture. If you see only two separate time points, describe the difference between those points; do not call it a sustained rise. If several categories are close, say they are similar rather than declaring a winner based on a barely visible gap. If the chart does not support a conclusion, leave it out. Do not infer causes from a pattern unless the supplied material establishes them.

Hypothetical example: suppose a fictional chart compares sign-ups for three workshops in April: Cedar, 18; Maple, 20; and Birch, 9. A supported overview is: “Maple had the most sign-ups, Cedar was close behind, and Birch had fewer.” That communicates the comparison without reciting each bar label or claiming why the counts differ.

Assuming those fictional labels and counts are the complete chart data, you could use this planning outline:

Short description: “A bar chart compares April sign-ups for three workshops. Maple had the most sign-ups, Cedar was close behind, and Birch had fewer.”

Fuller detail, if exact counts are needed: “The chart uses workshop names as categories and sign-up counts as values. Cedar: 18; Maple: 20; Birch: 9.”

The short version tells readers what is compared and the main visible comparison. The second part preserves the exact values for someone who needs them. You could present the values in an accompanying structured table instead of repeating them in prose. For a chart whose visual arrangement matters, include that detail only if you can verify it—for example, whether a particular segment is highlighted or categories are grouped. WAI’s guidance supports an overview plus access to essential information; it does not establish which details are essential for every chart, so use the chart’s purpose and context to decide. [S1]

Compare each sentence against the chart itself, not against what you expect the data to mean. Confirm the title, units, category names, and any stated values. Check that the overview does not hide a meaningful comparison, overstate a pattern, or imply a cause. If you cannot read a value or verify a visual feature, omit it or flag it for someone with access to the underlying data to check.

A quick editing test: could a reader understand the chart’s subject and main supported feature from the overview? Could they find exact values elsewhere if they need them? If both answers are yes, you are likely giving orientation without making the overview carry every data point. Keep the description grounded in the supplied chart; the example above is hypothetical, not evidence about any real workshop.