Alt Text Checker

Alt Text Checker evaluates the alt text you paste, not the image itself. It reads the string you would put in the alt attribute, weighs it against well-established guidance for descriptive text, and returns human-readable feedback on length, wording and usefulness. Because the input is the text rather than the picture, you can check alt text for any image at any stage, even before the graphic exists.

Alt text is the invisible paragraph of the web. It is what a screen reader announces in place of a picture, the description shown when an image cannot load, and a context signal for search engines trying to understand the subject of a page. Getting it right is one of the cheapest accessibility wins available, and one of the most commonly missed.

The checker applies heuristics built from how alt text actually behaves, not from any claim to understand your picture. It measures whether the string is long enough to describe anything and short enough to be consumed comfortably, flags the generic filler words that tell a reader nothing, such as image, photo or picture, and looks for the structural signals of a genuine description: concrete nouns, and wording that reads as an account of what the image contributes.

Some of the most important advice the tool encodes is negative. Decorative images legitimately carry empty alt text, and the checker is explicit that evaluating a description string is not the same as deciding whether an image should have one. Likewise, keyword stuffing is caught as a smell rather than rewarded, because text written for crawlers alone fails the humans who are the actual audience.

There is no image processing, no upload and no network step involved; the string is analyzed in the browser the moment you paste it. That also means there are no formats, pixel dimensions or 25 MB file concerns here: the only input is text, and the original image you might be describing is never touched by the workflow. The result is a tool that runs at typing speed, which matters precisely because alt text is evaluated by the dozens in real content operations rather than once per image in an idealized pipeline.

The realistic use cases mirror real publishing workflows. Content teams check draft alt text before a post goes live, editors audit strings handed over with a media library, and anyone pasting images from a CMS can validate the alt values Drupal, WordPress or a headless API produced. When the tool flags a string, the fix is a rewrite, and the loop is fast: revise, paste, read, publish. What the tool cannot do is see the picture or know the page, so the final say about whether a description is right always stays with you, and the checks simply surface the mechanical facts you judge against. A string that reads clean in isolation gives you that much more confidence in the page it supports.

Effective alt text answers one question about the image: what does it contribute to this page? For a photograph, the contribution is usually the content of the shot, so the alt text names the subject and the notable details. For a chart, the contribution is the takeaway. For a button, the contribution is the action it performs. The text serves the function of the image in the context of the document, not a catalogue of its pixels.

That functional view is why the same file deserves different alt text on different pages. A picture of a bicycle on a product page describes the product; the same picture in an article about urban commuting describes the scene, the rider or the setting. Good alt text is written against the page, and the checker rewards strings that read as a description of a specific contribution rather than a label for any random graphic.

• Name the subject early and plainly, without leading filler such as image of.
• Include the details that matter to someone who cannot see the picture.
• State the action for buttons and links, so the purpose survives the image.
• For charts and diagrams, convey the conclusion rather than restating the axis labels.
• Keep the sentence natural; if it sounds like a caption, it reads like alt text.

Most bad alt text falls into a small set of recognizable patterns, and the heuristics are tuned to catch exactly those. The empty-anyways string (image, photo, picture, graphic), the redundant echo (an image of a picture of), and the keyword dump are the classics. Each fails its audience differently, and the feedback points at the specific flaw rather than issuing a blanket verdict.

The strongest alt text is the least effortful: plain words in a natural order that state what is there. The checker does not insist on a formula, only that the string actually conveys something a reader could use.

Length guidance is practical rather than legal. A common reference point is to keep alt text under roughly 125 characters, because that is about the amount a screen reader user can comfortably hold while the rest of the page waits, and because most explanations of an image fit comfortably within it. Instead of a strict bound, describe what matters, then stop.

Too short is the more common failure: alt text of four words almost never tells a reader anything, because a subject alone without its contribution has still said nothing about the page. Too long is a different failure, a caption masquerading as alt text; when the description genuinely needs four sentences, the body text or a long-description attribute is the better home, and the alt text should summarize.

The checker flags both tails and explains the trade-off at each end, so a long but genuinely functional description is not punished; it is simply told where the balance sits.

No alt text exists in a vacuum, and the checker evaluates strings on their own merits precisely so you can weigh them against their context. The same photograph of a hiking trail deserves different wording for a product listing, a travel essay and a weather report, and the tool is most useful when you test several candidates and pick the one that reads true for the page it will live on.

Decorative images are the deliberate exception. When a picture adds no information, the accessible choice is empty alt text (alt equals an empty string) so the screen reader skips it entirely instead of reading out a file name or a meaningless label. The checker notes this decision honestly: it evaluates descriptive text, and the choice to omit a description for a decorative element is a valid outcome the tool will not second-guess.

The checker plugs into writing rather than image editing. Draft the alt text when you upload the image, paste it into the tool, read the feedback, and tighten the wording in the CMS field. Because the analysis is text-only and instant, it fits into the natural rhythm of composing a post without dragging in file handling.

Two habits keep it from becoming a check-the-box exercise. First, write the description from the page, not from the file name, so the alt text changes when the page changes. Second, treat a pass as a confirmation rather than an endpoint, because a string that passes every heuristic still depends on you having chosen the missing detail that the context needed.

• Paste the exact string you intend to place in the alt attribute.
• Read the feedback on length, filler words and descriptive structure.
• Rewrite against the page purpose, not against the tool.
• Re-check the revised string until the wording reads clean.
• Paste the final text into the CMS and publish.