Images with Alt Text Over 100 Characters: How to Fix It

This check flags images whose alt attribute runs longer than about 100 characters. It matters because bloated alt text is a chore to listen to on a screen reader and a sign the text has drifted from "describe the image" into keyword-stuffing or narration, neither of which helps users or search.

Why 100 characters is the line

Alt text has one job: give a person who can't see the image a concise stand-in for it. Screen readers read the whole attribute out loud, with no way to skim, so a 300-character alt turns one image into a paragraph the user must sit through. The ~100-character threshold isn't a hard rule from the spec — it's a practical ceiling that keeps you describing the image instead of writing an essay. Historically it also mapped to how much alt text search engines would meaningfully weigh. Go long and you get three problems at once: worse accessibility, diluted keyword relevance, and text that reads like spam.

A real failing example

Here's alt text that's trying to be a caption, a keyword list, and a sales pitch all at once — well over 100 characters:

<img src="running-shoe.jpg"
     alt="Best lightweight breathable running shoes for men and
     women, marathon training sneakers, blue mesh athletic
     footwear, buy running shoes online free shipping best price
     2026 top rated">

The fix describes what's actually in the frame, plainly, and stops:

<img src="running-shoe.jpg"
     alt="Blue mesh running shoe with white sole, side view">

Everything the bloated version was trying to do — rank for "buy," pitch free shipping — belongs in the page copy and metadata, not stuffed into an accessibility attribute.

Alt text length: what each range does

How to detect it on your own site

1. Crawl and sort by alt length. Screaming Frog's Images tab lists every alt value; export it and sort by character count to surface the offenders instantly. Best option for a full-site pass.
2. Inspect individual images. Right-click an image → Inspect in DevTools to read the raw alt. Useful for spot-checking a hero image or a specific template.
3. Run an accessibility auditor. Tools like axe DevTools or WAVE flag alt text that's overly long or looks like a filename, alongside missing-alt issues, so you catch both at once.
4. Grep the source or database. If you have template or DB access, a search for alt=" followed by a length filter finds patterns your CMS is generating — often the real culprit when hundreds of images fail together.

How to fix it

1. Describe, don't sell. Answer "what is in this image?" in one plain phrase. If you're mentioning price, shipping, or a keyword you want to rank for, you've left the lane.
2. Trim to the essentials. Cut articles and filler, drop "image of" and "picture of" (screen readers already announce it's an image), and keep the concrete detail that matters.
3. Move real detail to a caption. If an image genuinely needs a long explanation — a chart, a diagram — put that in a visible caption or nearby text, not the alt attribute.
4. Leave decorative images empty. Spacers, background flourishes, and icons that repeat adjacent text should use alt="" so screen readers skip them cleanly.
5. Fix the generator, not just the image. If a plugin auto-fills alt with the full post title plus tags, change that rule once. That's usually why the count is in the hundreds.
6. Re-crawl to confirm. Verify the long-alt count drops to zero across the set.

FAQ

Is 100 characters a hard limit from Google or WCAG?

No. Neither Google nor the WCAG spec sets a numeric cap. It's a widely used practical threshold: past roughly 100 characters, alt text tends to become tedious for screen-reader users and starts drifting toward keyword stuffing. Treat it as a strong guideline, not a law.

Will long alt text get me penalized for keyword stuffing?

You won't get a manual penalty for one long alt attribute, but cramming keywords into alt is exactly the kind of low-value signal that gets ignored or discounted. The keywords do more good in your visible copy, headings, and the image file name. See Image SEO Beyond Alt Text for where those signals actually belong.

What about complex images like charts and infographics?

Those are the legitimate exception. A chart may need more than 100 characters to convey its data. Even then, prefer a short alt plus a full text description in a caption or adjacent paragraph, so sighted and non-sighted users both get the detail.

How is this different from missing alt text?

Missing alt gives the user nothing; over-long alt gives them too much of the wrong thing. Both are quality failures on the same attribute. If your audit also flagged blank alts, fix those first — see Images Need Alt.

Does alt text help images rank in Google Images?

Yes, concise and accurate alt text is a real signal for Google Images, along with the file name, surrounding text, and structured data. Long stuffed alt undercuts that relevance. Our image SEO study breaks down which factors move the needle.