THE WORKDAY TOOLKIT · Updated October 28, 2026
A slide says “Project progress” above a chart with three colored bars. A colleague using a screen reader needs the conclusion, not a list of colors. AI can draft a first description, but the chart owner must check the values and decide what the chart is meant to say.
Quick answer: Give ChatGPT the chart image and its verified data or caption. Ask for one short alt text sentence and a separate longer explanation when the chart carries more detail. Check every label, unit, comparison and direction against the source before putting the text in PowerPoint.
What good chart alt text does
The World Wide Web Consortium’s complex images guidance recommends a short text alternative that identifies and summarizes a complex image, with the fuller information available nearby or through a longer description. For a chart, lead with its message in the context of the slide. A complete data table may belong in the document or notes rather than one crowded alt text field.
For example, “Bar chart with blue, green and gray bars” names the visual form but leaves out the meaning. “Bar chart showing the pilot group rising from 12 to 18 completed tasks while the comparison group stays at 12” is more useful if those figures and the comparison are verified. These figures are a fictional editorial example, not the result of a tool test.
A four-step workflow
- Confirm the chart source. Record the title, category names, units, time period and values from the workbook or data table. Decide the one point the slide is making.
- Attach the chart image. ChatGPT supports image inputs, but its ability to read small text, precise positions or complex visuals has limits. Provide the verified labels and values in the prompt as well.
- Ask for two outputs. Request a concise alt text sentence and, if needed, a longer description or accessible data table. Keep interpretation separate from observed data.
- Review and add it. Compare the draft against the workbook and chart. Select the chart in PowerPoint and edit its Alt Text; run the Accessibility Checker and review the result in the surrounding slide.
OpenAI documents image input capabilities and limitations. Microsoft explains how to add alt text to a chart or other object and recommends reviewing automatically generated descriptions. Menu labels can vary by Office version.
Copy a prompt that separates facts from interpretation
Draft accessible text for the attached chart on a work slide. Use these verified facts rather than estimating values from pixels: - Chart title: [title] - Time period and unit: [period, unit] - Categories and values: [paste from source table] - Main point the slide should convey: [one sentence] Return: 1. One concise alt text sentence describing the chart's purpose and main takeaway. 2. A separate longer description if a reader needs the values. 3. A list of any labels, values or claims you could not verify. Do not invent numbers, causal explanations or trends. Do not say a change is statistically significant unless the source explicitly provides a valid analysis. Do not modify files.
This prompt makes the data table the authority. If you cannot provide reliable values, ask for a description of the visible structure only, mark uncertain labels, and verify the chart yourself before publishing.
A worked editorial example
Suppose a fictional slide compares completed tasks in two groups. The verified source table is: pilot group 12 before and 18 after; comparison group 12 before and 12 after. An appropriate short description could be: “Bar chart showing completed tasks rising from 12 to 18 in the pilot group while remaining at 12 in the comparison group.” If the slide is about a different point, change the sentence to match its purpose.
A longer nearby description can name the two periods and all four values. Avoid adding “AI caused the increase.” The chart alone does not establish causation.
When to use AI, and when to write it yourself
- Simple chart with a clear takeaway: write the sentence yourself or use AI only to shorten it.
- Many labels or series: supply a verified table and use AI to organize a draft; provide the full values elsewhere.
- Confidential presentation: follow your organization’s approved AI and data-sharing rules before uploading.
- Image-only or tiny labels: get the original workbook or a legible export first. Do not accept guessed values.
The final test is practical: someone hearing the description should understand why the chart is on that slide. A short summary plus accessible details serves that goal better than a long recitation in the alt text field.
Related reading: For checking numbers in a written summary, see why a 50% increase is not “double”. For selecting tools around a real task, see seven checks before paying for an AI tool.
Sources checked October 28, 2026: W3C WAI complex images; OpenAI image inputs; Microsoft alt text instructions.