Chart and Graph Alt Text: What 12 Real Ones Say
By AutoBoost Team · 2026-10-29 · 7 min read
Every chart image on the two ONS bulletins we checked had empty alt text: 11 on the consumer price inflation bulletin and 8 on the GDP bulletin. On 29 October 2026 we fetched the HTML of pages on 43 sites, looking for charts and graphs in news, data and report pages. 30 sites loaded and 10 blocked us or did not respond, so we skipped them. 3 more had no page at the address we tried. Many of the 30 that loaded hid their charts in scripts or iframes, so no alt text was visible to read. This guide uses 12 charts from 7 sites where the alt text sat in the page source. Each is quoted exactly as it appears in the HTML, with the page it came from.
Key takeaways
- Only 3 of the 12 charts had alt text that told you what the chart shows. 7 had a clear fault.
- The most common fault was no description at all: 2 missing, 1 empty and 2 that just say "Chart".
- The good examples gave the chart type, the measure and the main point, in 108 to 146 characters.
- On the ONS pages we checked, every chart image had empty alt text, 19 images across the two bulletins.
Twelve charts and their alt text
| Site | Alt text | Characters | Verdict |
|---|---|---|---|
| Bank of England, Monetary Policy Report August 2025 | Shaded fan chart for the unemployment rate projection. The distribution widens over the forecast period to reflect uncertainty around the outlook. | 146 | Good |
| Bank of England, Monetary Policy Report August 2025 | Inflation is currently above the 2% target. It is projected to rise further to a peak of 4.0% in September. | 108 | Good |
| Bank of England, Monetary Policy Report August 2025 | Headline GDP growth is expected to slow down to 0.1% in 2025 Q2 before picking up again in 2025 Q3. The unemployment rate rises slightly to 4.8% by 2025 Q3, and CPI inflation is expected to peak at 4.0% in September. | 216 | Fine: useful but too long |
| Our World in Data, CO2 and greenhouse gas emissions | Grid of charts showing the percentage increase in GDP per capita and the percentage decrease in CO2 emissions per capita, for many countries. | 141 | Good |
| Our World in Data, CO2 and greenhouse gas emissions | Missing (temperature change chart, no alt attribute) | 0 | Fault: missing |
| Wikipedia, Economy of the United Kingdom | Unemployment rate, 1881–2025 | 28 | Fine: names the chart, not the point |
| Wikipedia, Inflation | Missing (world inflation rate chart, no alt attribute) | 0 | Fault: missing |
| Statista, EU contributors and beneficiaries | Infographic: Which Countries are EU Contributors and Beneficiaries? | Statista | 78 | Fault: page title with "Infographic" and brand name, no data |
| Pew Research Center, job growth in AI-exposed occupations | Chart | 5 | Fault: says only "Chart", same alt on both charts on the page |
| Pew Research Center, how Americans engage with news online | Chart | 5 | Fault: says only "Chart", same alt on three different charts |
| ONS, Consumer price inflation, UK | Empty | 0 | Fault: empty on a chart that carries information |
| Economics Help, the German economic model | germany-lags-behind-gdp-per-capita | 34 | Fault: file name |
A few notes on the table. The Statista alt text is an exact copy of the page title plus the site name. The Pew "Chart" images are the fallback pictures of its interactive charts. The ONS bulletin shows each chart with a title nearby, but the image itself tells a screen reader nothing. The second ONS page we checked, the GDP first quarterly estimate at https://www.ons.gov.uk/economy/grossdomesticproductgdp/bulletins/gdpfirstquarterlyestimateuk/latest, also had empty alt text on all 8 of its chart images.
Seven faults, and why empty is wrong for a chart
Counted from the table, 7 of the 12 had a fault.
- Missing alt attribute: 2. Both on very large reference sites. A screen reader may read out the file name instead. On Our World in Data, the same chart also appears further down the page as a linked card with a different alt text ("A thumbnail of the ... chart"), so one chart has two descriptions, one of which is a label for a thumbnail.
- Generic word: 2. Pew uses "Chart" for every chart, so a page with three charts gives three identical alt texts that mean nothing.
- Empty alt: 1 in the table, and 19 chart images across the two ONS bulletins. Empty alt text is right for decoration. A chart is not decoration.
- File name: 1. "germany-lags-behind-gdp-per-capita" is the upload name. It does hint at the point, but nobody wrote it for a reader.
- Title and brand name: 1. Statista repeats the page title with "Infographic:" at the front and "Statista" at the end.
The other 5 were good or fine. Nothing we found was keyword stuffed. The mistakes on charts were not too much text but too little.
Type, measure, main point
The three good examples came from the Bank of England and Our World in Data, and they have the same shape.
- They name the chart type. "Shaded fan chart" and "Grid of charts" tell a listener what kind of picture they are missing.
- They name the measure. Unemployment rate, inflation, GDP per capita, CO2 emissions per capita. The unit is there too: percentages, per capita.
- They give the main point. "Inflation is currently above the 2% target. It is projected to rise further to a peak of 4.0% in September." That one sentence is what a sighted reader takes from the line.
- They give a few key numbers, not all of them. The 2% target and the 4.0% peak are enough. Nobody needs every point on the line read out.
Left out of the good ones:
- Colours and line styles.
- Padding such as "image of" or "chart showing". The chart type does that job in the first two words.
- Axis labels and every data point. If readers need the full numbers, put a data table or a link to the data on the page.
- A copy of the page title or the brand name.
The Wikipedia example, "Unemployment rate, 1881–2025", is a fair middle ground. It names the measure and the date range but not the finding, so a listener still has to go and find the point in the text.
One or two sentences is the right length
From the 9 examples with text, the two shortest said nothing useful: "Chart" at 5 characters and the file name at 34. "Unemployment rate, 1881–2025" at 28 characters named the chart but not the point. The three good ones ran from 108 to 146 characters, which is one or two sentences. The longest, at 216 characters, gave three separate figures. It reads well, but it is too much for alt text. Shorten it to the main point and put the other numbers in the text beside the chart.
A working rule from this sample: aim for one or two short sentences, around 100 to 150 characters, and cut anything the page already says beside the chart.
Tip: rename the export, then describe the point
Charts exported from spreadsheets and tools usually land in the media library under whatever name the export or screenshot tool gave the file, with no alt text at all. That matches the missing and file-name faults above. When you check a draft for a chart, ask whether it names the type, the measure and the main point. Related image types are covered in our guides to infographic alt text, table alt text and diagram alt text, and the main bulk alt text guide covers the whole library.
Install the free AutoBoost SEO plugin to connect WordPress to the AutoBoost SEO app. The app writes missing alt text for the images in your posts in bulk. You approve each one, and it saves to the post and the media library.