Free alt text checker
An alt text checker that lists every image on a page and flags the ones missing alt text — the gap that leaves images invisible to screen readers and to Google Images alike. It separates a genuinely missing attribute from a deliberately empty one, so you fix what needs fixing.
Two problems, one attribute
Alt text sits at the exact point where accessibility and SEO are the same job. A screen reader needs the description to tell a blind visitor what the image shows; Google needs it to understand and rank the image. Get it right and you serve both at once. Leave it off and you fail both at once — the screen reader reads out a meaningless file name, and the image contributes nothing to search. That overlap is why this is one of the highest-leverage small fixes on most pages.
Missing is not the same as empty
The distinction this tool draws is the one that matters. A missing alt attribute is a mistake to fix. An empty alt attribute is a decision: it tells assistive technology the image is decorative and safe to skip, which is exactly right for a divider, a background texture or a spacer that carries no information. A tool that only counts “images without alt text” muddles the two and sends you off to write descriptions for images that should not have any. This one keeps them separate.
What good alt text reads like
Describe the image plainly, as you would to someone on the phone who cannot see it. Keep it to a sentence. Do not open with “image of” — the screen reader already says that. If the image contains words, include them. Resist the urge to pack in keywords; alt text that reads like a search query helps nobody and can be flagged as spam. The density of your actual page copy is a separate question — the keyword density checker is the tool for that.
Where this fits
Alt text is one accessibility and on-page signal among many. The images also need the right social preview tags, and the page needs correct metadata to be found at all — the Open Graph checker and the meta tag checker cover those. For the whole picture in one pass, the free website checker audits accessibility alongside speed, technical SEO and metadata and scores it out of 100, and what counts as a good score explains how to read that number.
Alt text questions
- What does an alt text checker do?
- An alt text checker fetches a page, finds every image in its HTML, and reports the alt attribute on each one — flagging the images that have no alt attribute at all, and separating them from images that carry a deliberately empty alt. It turns a check you would otherwise do by reading source code by hand into a single list you can scan in seconds.
- What is alt text and why does it matter?
- Alt text is a short written description of an image, carried in the img tag's alt attribute. It does two jobs: a screen reader reads it aloud to a visitor who cannot see the image, and a search engine uses it to understand what the image shows, which is how images earn a place in Google Images. An image with no alt text is invisible to both — a real gap for accessibility and a missed opportunity for search.
- What is the difference between missing and empty alt text?
- A missing alt attribute (no alt at all) is almost always a mistake: a screen reader falls back to reading the file name, which is useless. An empty alt attribute (alt="") is a deliberate signal that the image is purely decorative and should be skipped — the correct choice for a background flourish or a spacer. This tool flags the two differently, because a missing attribute needs fixing and an empty one on a decorative image is correct.
- How do I write good alt text?
- Describe what the image shows, literally and briefly, as if to someone who cannot see it. Skip 'image of' or 'picture of' — the screen reader already announces it as an image. Keep it to a sentence, include any text that appears in the image, and only mention the subject that matters to the page. For a purely decorative image that adds no information, use an empty alt attribute so it is skipped rather than described.
- Does alt text help SEO?
- Yes, in two ways. It is the primary signal Google uses to rank an image in Google Images, which is its own source of traffic. And because alt text describes the image in words on the page, it adds relevant context that supports the page's overall topic. It is not a place to stuff keywords — a description that reads naturally serves both the screen-reader user and the search engine, and keyword-stuffed alt text can be treated as spam.
- Does this find images loaded by JavaScript?
- It reads the HTML the server sends, so it finds every image present in the initial markup — which is what a search engine crawls first and what loads fastest for a user. Images injected later by JavaScript after the page runs are not in that HTML and are not counted. For SEO that is usually the right scope, since server-rendered images are the ones most reliably indexed.
- How do I write good alt text for images?
- Good alt text describes what the image shows and why it is on the page, in a plain sentence a person could picture without seeing it. Keep it specific rather than keyword-stuffed, skip phrases like 'image of', and leave the alt empty for purely decorative images so screen readers can ignore them.
- How long should alt text be?
- Alt text should be a short, complete description, usually well under about 125 characters, because many screen readers cut off around there. Say what matters and stop — if an image genuinely needs a long explanation, put that in the surrounding text and keep the alt concise.
- Should every image have alt text?
- Every meaningful image needs alt text so it is accessible and can appear in image search, but purely decorative images should have an empty alt attribute rather than a description. An empty alt tells assistive technology to skip the image, which is correct when it carries no information.
- What is the difference between alt text and a caption?
- Alt text is read by screen readers and shown when an image fails to load, describing the image for people who cannot see it, while a caption is visible text below an image that everyone reads. They serve different audiences, so a good caption does not remove the need for alt text.
- Does alt text help images rank in Google Images?
- Alt text is a primary signal Google uses to understand what an image depicts, so descriptive, accurate alt text does help images surface in Google Images for relevant searches. It works alongside a descriptive file name and the text around the image, not on its own.