{"id":1050,"date":"2026-06-23T13:33:47","date_gmt":"2026-06-23T13:33:47","guid":{"rendered":"https:\/\/dev-rankmetryblog.pantheonsite.io\/?p=1050"},"modified":"2026-08-05T21:20:55","modified_gmt":"2026-08-05T21:20:55","slug":"alt-text","status":"publish","type":"post","link":"https:\/\/rankmetry.com\/blogs\/alt-text\/","title":{"rendered":"What Is Alt Text? Why It Matters and How to Write"},"content":{"rendered":"\n

Alt text (alternative text) is a short written description added to an image through the HTML alt attribute. It does two jobs at once. It tells screen reader users what an image shows, and it gives search engines<\/a> like Google the context they need to index that image.
Keep it descriptive and under about 125 characters, work your target keyword in only when it fits the description honestly, and leave it empty (alt=””) for purely decorative images. Done right, it improves accessibility and opens up Google Images as a traffic source.<\/p>\n\n\n\n

What Is Alt Text? The HTML Attribute That Serves People and Search Engines at Once<\/h2>\n\n\n\n


I’ll be straight with you: alt text is one of the most undervalued lines of code on a web page. It takes ten seconds to write, most teams skip it or stuff a keyword into it, and both mistakes cost something real. I’d treat it as a required field on every meaningful image, not an optional extra, and I’ll explain why over the next few sections. This guide covers what alt text is, the dual purpose behind it, how to write it well, when to leave it blank, and how it quietly feeds image SEO.<\/p>\n\n\n\n

What is alt text, and where does it live in your code?<\/h2>\n\n\n\n

Alt text is a written description of an image that sits inside the image’s HTML. You will also hear it called image alt text, an alt tag, or simply alternative text; they all point to the same thing. In plain terms, the alt attribute is a slot inside the <img> tag where you describe what the picture shows. Here is what it looks like:<\/p>\n\n\n\n

<img src=”golden-retriever-puppy.webp” alt=”Golden retriever puppy chewing a tennis ball on a lawn”><\/mark><\/strong><\/p>\n\n\n\n

The text inside the quotes is the alt text. Most visitors never see it, because the image loads and the description stays in the background. It surfaces in three situations: when the image fails to load and the browser shows the text in its place, when a screen reader reads the page aloud, and when a search engine crawler reads the page to figure out what the image depicts.<\/p>\n\n\n\n

People mix up alt text with two related things, so here is the distinction in one place, including the common alt text vs title question.<\/p>\n\n\n\n

Element<\/strong><\/td>Where it appears<\/strong><\/td>Main job<\/strong><\/td><\/tr><\/thead>
Alt text (alt)<\/td>Inside the <img> tag, invisible unless the image fails<\/td>Describes the image for screen readers and search engines<\/td><\/tr>
Title attribute (title)<\/td>Tooltip on mouse hover, in some browsers<\/td>Optional extra; minor value, not a replacement for alt text<\/td><\/tr>
Caption<\/td>Visible text below or beside the image<\/td>Context and commentary for every reader<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Why does alt text matter twice over, for people and for search?<\/h2>\n\n\n\n

This is the part most explanations rush. Alt text earns its keep in two separate systems, and the same sentence has to satisfy both.<\/p>\n\n\n\n

For accessibility, alt text is the only way a screen reader user knows an image exists and what it contains. Software like JAWS, NVDA, and VoiceOver reads the alt attribute out loud, behavior documented at length by accessibility authorities like WebAIM<\/a>. With no alt text, the reader hears a filename or nothing at all, and the meaning of the image is gone. The Web Content Accessibility Guidelines<\/a> treat a text alternative for non-text content as a baseline requirement, which is why alt text shows up in nearly every accessibility audit and, in many regions, in legal obligations tied to standards like the WCAG.<\/p>\n\n\n\n

For SEO, the logic is just as simple. Search engines cannot see an image the way you do. According to Google Search Central<\/a>, Google reads the alt text alongside its own computer vision models and the surrounding page content to work out what an image is about. So alt text for SEO<\/a> is less about gaming a keyword and more about feeding context to systems that are otherwise reading blind: the computer vision guesses, and your description confirms. That alt text is the most important piece of metadata you can attach to an image for search. There is also a detail Google states that most write-ups leave out: when you use an image as a link, the alt text acts as the anchor text for that link, which means a vague description wastes a ranking signal you did not know you had. It is also worth remembering that search engine crawlers, the same Google bot that reads your page copy, are the ones parsing that attribute.<\/p>\n\n\n\n

The two purposes reinforce each other more than they compete, and the data backs that up. In a study of more than 800 websites published by AccessibilityChecker.org in June 2026, 73.4% of sites saw organic traffic rise after implementing accessibility improvements<\/a>, with the average site gaining around 12% more traffic within three months. Alt text is one of the most basic accessibility elements, so it sits right at the center of that overlap. Treat accessibility as the goal and search benefits tend to follow.<\/p>\n\n\n\n

How do you write good alt text?<\/h2>\n\n\n\n

Here is the method I use on client audits, stripped to the parts that matter. These alt text best practices satisfy the screen reader and the search engine in the same line.<\/p>\n\n\n\n

    \n
  1. Describe what is actually in the frame.<\/strong> Not “dog.” Say “golden retriever puppy chewing a tennis ball on a lawn.” The more specific the description, the more useful it is to a screen reader user and the clearer the signal to a crawler.<\/li>\n\n\n\n
  2. Keep it tight, roughly 125 characters or fewer.<\/strong> That length keeps it easy for a screen reader to speak in one breath and concise enough for a search engine to parse. If you are writing two sentences, you are probably over-describing.<\/li>\n\n\n\n
  3. Match the image to the page’s purpose.<\/strong> An image of a chart on a page about quarterly revenue should describe the data trend, not the color of the bars. Context is part of the description.<\/li>\n\n\n\n
  4. Work the keyword in only when it fits.<\/strong> If your page targets “vegan chocolate mousse” and the photo genuinely shows it, “chocolate avocado mousse in a glass jar” earns its place. If the photo is a stock office scene, forcing the keyword in is dishonest and search engines treat it as spam.<\/li>\n\n\n\n
  5. Skip “image of” and “picture of.”<\/strong> Screen readers already announce that it is an image, so those words just waste space.<\/li>\n<\/ol>\n\n\n\n

    The single biggest mistake is keyword stuffing. Google’s own documentation shows the failure mode with an alt attribute crammed full of “puppy dog baby dog pup pups puppies doggies” and so on, and flags it as the kind of thing that can get a page seen as spam. Cramming terms in makes the text unreadable for the people who depend on it and hands you no SEO upside. Write for the human first and the keyword question mostly answers itself. If you want the deeper mechanics of keyword placement across a page, our on-page SEO fundamentals (INTERNAL LINK PLACEHOLDER: on-page SEO)<\/em> cover where keywords genuinely move the needle.<\/p>\n\n\n\n

    What does good versus bad alt text actually look like?<\/h2>\n\n\n\n

    Examples make this concrete faster than rules do. These alt text examples each describe the same hypothetical image, weak version beside strong version.<\/p>\n\n\n\n

    Image<\/strong><\/td>Weak alt text<\/strong><\/td>Strong alt text<\/strong><\/td><\/tr><\/thead>
    Product photo<\/td>alt=”bag”<\/td>alt=”Pink leather Chanel flap bag with gold chain strap”<\/td><\/tr>
    Blog header<\/td>alt=”gardening gardening tips garden how to garden”<\/td>alt=”Woman planting basil in a raised garden bed”<\/td><\/tr>
    Data chart<\/td>alt=”chart”<\/td>alt=”Bar chart showing organic traffic rising 40% from January to June 2026″<\/td><\/tr>
    Team photo<\/td>alt=”IMG_4471″<\/td>alt=”RANKMETRY team at the 2026 strategy offsite in Lahore”<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

    Notice the pattern. The weak versions are either empty of meaning, stuffed with repeated terms, or left as a raw filename. The strong versions read like something you would say out loud if you were describing the picture to a friend on the phone. That is the bar. If you would not say it aloud, do not write it.<\/p>\n\n\n\n

    When should alt text be empty?<\/h2>\n\n\n\n

    Here is the nuance almost nobody explains properly, and knowing when to leave alt text empty is what separates a careful implementation from a sloppy one: sometimes the right alt text is no text at all. Purely decorative images, the swooshes, dividers, background flourishes, and spacer graphics that add nothing to the meaning of the page, should carry an empty alt attribute:<\/p>\n\n\n\n

    <img src=”divider-line.png” alt=””><\/p>\n\n\n\n

    That is alt=”” with nothing between the quotes, not a missing attribute. The difference matters. An empty alt tells a screen reader to skip the image entirely, which keeps the experience clean for someone listening to the page. A missing alt leaves the screen reader guessing, and many will read out the filename, which is noise. So the rule is not “always write alt text.” The rule is “always make a decision”: describe it if it carries meaning, empty it if it is decoration.<\/p>\n\n\n\n

    How do you tell the difference? Ask whether the page would lose any information if the image vanished. If the answer is no, it is decorative and the alt stays empty. If a sighted reader would learn something from the image that a blind reader would otherwise miss, it needs a real description. The W3C’s images tutorial and decision tree<\/a> is the reference I send clients when this call gets tricky.<\/p>\n\n\n\n

    How Google Cloud Vision AI reads your images (and where alt text fits in)<\/h2>\n\n\n\n

    Earlier I said Google reads alt text \u201calongside its own computer vision models.\u201d Google Cloud Vision AI is exactly those models. Understanding what they do makes it clearer why your description matters and what job it is actually doing.<\/p>\n\n\n\n

    What the Vision API does automatically<\/strong><\/h3>\n\n\n\n

    When Google crawls a page with an image, its Vision API runs object and label detection on the image pixels. It returns a list of labels with confidence scores, something like: dog (0.97), outdoor (0.91), grass (0.88), ball (0.79). That is the machine\u2019s best guess. Your alt text is the human confirmation that either agrees, corrects, or adds specificity that pixel analysis cannot produce on its own.<\/p>\n\n\n\n

    Three Vision AI capabilities and what they mean for your alt text<\/strong><\/h3>\n\n\n\n
      \n
    • Label detection<\/strong> Vision AI scans pixels and assigns broad labels. A product photo of a walnut dining chair might come back as \u201cfurniture, wood, chair.\u201d Your alt text \u201cwalnut mid-century dining chair with woven seat\u201d sharpens that into something a shopper would actually search for.<\/li>\n\n\n\n
    • Visual captioning (Imagen)<\/strong> Google\u2019s Imagen model can auto-generate a caption for an image. Think of this as the machine writing its own alt text. The catch is that auto-captions are generic. \u201cA person gardening\u201d is accurate but useless for ranking \u201chow to grow basil in a raised bed.\u201d A human-written alt attribute beats an auto-caption every time because you know the page context the model does not.<\/li>\n\n\n\n
    • OCR (text in images)<\/strong> Vision AI reads text embedded in images, so if your infographic contains the words \u201cRevenue up 40% YoY,\u201d Google can extract that. But it cannot read your intent. An alt attribute like \u201cBar chart showing organic traffic rising 40% from January to June 2026\u201d adds the \u201cwhat this means for the reader\u201d layer that OCR alone cannot produce.<\/li>\n<\/ul>\n\n\n\n

      Side-by-side examples: Vision AI label vs. human alt text<\/strong><\/h3>\n\n\n\n

      The table below shows what Vision AI would likely return on its own versus what a well-written alt attribute adds on top of it.<\/p>\n\n\n\n

      Image<\/strong><\/td>Vision AI auto-label<\/strong><\/td>Human alt text (what you write)<\/strong><\/td><\/tr><\/thead>
      Product photo<\/td>furniture, wood, chair, indoor<\/td>Walnut mid-century dining chair with woven seat<\/td><\/tr>
      Recipe photo<\/td>food, dessert, chocolate, plate<\/td>Chocolate avocado mousse in a glass jar topped with cocoa powder<\/td><\/tr>
      Data chart<\/td>diagram, chart, text, colorfulness<\/td>Bar chart showing organic traffic rising 40% from January to June 2026<\/td><\/tr>
      Team photo<\/td>people, group, smile, indoor, event<\/td>RANKMETRY team at the 2026 strategy offsite in Lahore<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n


      The pattern is consistent: Vision AI sees what is there, but not what it means on your page. Your alt text closes that gap. Write for a reader who cannot see the image, and you are automatically writing what the machine needs to confirm its guess with confidence.<\/p>\n\n\n\n

      Can alt text really bring traffic from Google Images?<\/h2>\n\n\n\n

      Yes, and this is the part teams leave on the table (INTERNAL LINK PLACEHOLDER: image SEO)<\/em>. Google Images is a search engine in its own right, and tools like Google Lens have turned visual search into a genuine discovery channel. A shopper can point Google Lens at a chair in a cafe and get matched to retailers selling it, and accurate alt text is part of how those matches get made. When your images carry accurate, descriptive alt text, search engine crawlers can match them to relevant visual searches with more confidence, which means your photos can surface in front of people who would never have found your page through a normal text search.<\/p>\n\n\n\n

      Some site types gain more than others here. Ecommerce stores, recipe sites, travel blogs, design portfolios, and how-to guides all live and die on visual content, so for them image SEO is not a side quest. A furniture retailer whose product shots all read alt=”IMG_2231″ is invisible in image search; the same catalog with descriptions like “walnut mid-century dining chair with woven seat” can pull steady traffic from people shopping with their eyes.<\/p>\n\n\n\n

      How does alt text fit into AI and visual search now?<\/h2>\n\n\n\n

      A quick, honest note on where this is heading, because I would rather flag uncertainty than oversell it. As of mid-2026, AI-driven and multimodal search tools increasingly interpret images using their own vision models, which has led some people to assume alt text is becoming optional. I would not bet on that. Vision models still lean on textual context to confirm what they are looking at, and alt text remains the cleanest, most explicit description you can hand a machine.
      The durable signals, accurate descriptions, real page relevance, and clean structure, are exactly what both classic crawlers and newer AI systems reward. The specific mechanics will keep shifting, so treat any “AI ignores alt text now” claim with suspicion and keep writing good descriptions. For the wider picture on optimizing for these systems, see our guide to answer engine optimization (INTERNAL LINK PLACEHOLDER: answer engine optimization)<\/em>.<\/p>\n\n\n\n

      Frequently asked questions about alt text<\/h2>\n\n\n\n

      How long should alt text be?<\/strong><\/h3>\n\n\n\n

      There is no hard alt text character limit enforced by browsers, but aim for roughly 125 characters or fewer. That length is short enough for a screen reader to read in a single pass and concise enough for a search engine to interpret cleanly. If your description runs longer than a sentence, you are likely describing detail that does not help. Complex images like detailed infographics are the exception and may need a longer description elsewhere on the page.<\/p>\n\n\n\n

      Should every image have alt text?<\/strong><\/h3>\n\n\n\n

      Every meaningful image should, but not every image. Decorative graphics that add no information, dividers, background textures, spacers, should carry an empty alt attribute so screen readers skip them. The goal is a deliberate choice for each image: describe it or empty it, never just leave the attribute off.<\/p>\n\n\n\n

      Do keywords in alt text help rankings?<\/strong><\/h3>\n\n\n\n

      A relevant keyword that fits the honest description can help search engines understand the image’s context. A keyword forced into a description that does not match the image is keyword stuffing, which Google may treat as spam. Describe the image accurately first; if your target term belongs in that description, it will appear naturally.<\/p>\n\n\n\n

      What is the difference between alt text and the title attribute?<\/strong><\/h3>\n\n\n\n

      Alt text describes the image for screen readers and search engines and shows when the image fails to load. The title attribute produces a tooltip on hover, is only available to mouse users, and carries minimal SEO or accessibility value. Alt text is the one that matters; the title attribute is optional and usually unnecessary.<\/p>\n\n\n\n

      Does alt text directly affect Google rankings?<\/strong><\/h3>\n\n\n\n

      Not as a standalone ranking factor for your page. It helps Google understand and index your images, which strengthens image search visibility and reinforces what your page is about. Think of it as context that supports your overall relevance rather than a switch that lifts rankings on its own.<\/p>\n\n\n\n

      How do I add alt text in WordPress?<\/strong><\/h3>\n\n\n\n

      In the block editor, click the image, open the block settings, and fill in the “Alternative Text” field. The platform writes it into the alt attribute for you. Most page builders and CMS platforms offer the same field, usually labeled “alt text” or “alternative text,” in the image settings.<\/p>\n\n\n\n

      Is alt text legally required?<\/strong><\/h3>\n\n\n\n

      In many jurisdictions, accessibility laws tied to standards like the WCAG expect text alternatives for images, so missing alt text can be part of a compliance gap. Requirements vary by country and sector, so this is general information rather than legal advice. If compliance is a concern for your organization, confirm your specific obligations with a qualified professional.<\/p>\n\n\n\n\n