Learning how to write alt text for SEO is one of the highest-return on-page skills you can pick up in 2026. It takes under a minute per image, yet most sites leave half their images with blank, auto-generated, or keyword-stuffed alt attributes. The result: screen readers stumble, Google Images ignores your visuals, and your pages send weaker topical signals than they should. This guide gives you the exact formula, ten real before-and-after rewrites, a WordPress fix-up workflow, and the 2026 angles (AI Overviews, Google Lens) that older guides miss.
This is your complete playbook for how to write alt text for SEO — from the five-part formula to ten before-and-after examples you can copy today.
What Alt Text Actually Is (and What It Is Not)
Alt text — short for alternative text — is a written description of an image embedded in the HTML of your page:
<img src="trail-running-shoes.jpg" alt="Pair of blue trail running shoes with red laces on a rocky mountain path">
Its primary job is accessibility: screen readers read it aloud to visually impaired users, and browsers display it when an image fails to load. Its secondary job is SEO: search engine crawlers are still fundamentally text-based, so alt text is the clearest signal you give them about what an image shows.
It is commonly confused with two other things:
- Title text — the tooltip that appears when someone hovers over an image. It carries almost no SEO weight and is not read by screen readers. Never use it as an alt text substitute.
- Image file name — the name of the uploaded file, like
trail-running-shoes.jpg. Descriptive, keyword-aware file names support your alt text, but they do not replace it.
Understanding these distinctions is the foundation of how to write alt text for SEO correctly, because treating alt text, title text, and file names as interchangeable is the most common beginner error.
Why Alt Text Matters for SEO in 2026
Google Images is a search engine in its own right, and a meaningful slice of discovery traffic starts there. When someone searches for a product or a how-to visual, Google matches their query against the textual signals around your images — and alt text is the strongest of those signals. Pages whose images carry precise alt text consistently earn more image-search impressions than identical pages with blank alt attributes. If you are serious about learning how to write alt text for SEO, image search is the fastest place to see a payoff.
If you are still on the fence, consider this: learning how to write alt text for SEO is one of the highest-ROI on-page tasks because it improves accessibility and image discovery at the same time.
Alt text also reinforces the topic of the entire page. If your article targets “trail running for beginners” and your images describe “blue trail running shoes on a rocky mountain path” and “runner tying trail shoes before a forest run,” every one of those descriptions is another contextual vote telling Google what the page is about.
There is also an honesty point worth making: alt text is not a magic ranking lever for web search. Stuffing keywords into alt attributes will not move a page from position 40 to position 4. What it does is remove friction — accessibility friction for users, and understanding friction for crawlers — and in 2026, with AI-powered search leaning harder on structured understanding of your content, removing that friction matters more than ever.
Fortunately, how to write alt text for SEO is a learnable, repeatable skill rather than guesswork — the formula below makes it mechanical. Google’s own image SEO best practices confirm that descriptive alt text helps Google understand your images.
How to Write Alt Text for SEO: The 5-Part Formula
Here is the repeatable method for how to write alt text for SEO that balances accessibility, search signals, and readability. Apply it to every meaningful image you publish.
1. Describe what you actually see (5–12 words)
Imagine describing the image to someone over the phone. Lead with the main subject, then one or two distinguishing details: color, setting, action, or model number. Specifics beat generics every time — “Dell XPS 13 laptop, silver finish, half-open on a wooden desk” beats “laptop.”
2. Add context from the page
The same photo needs different alt text on different pages. A picture of running shoes on a product page should name the model and variant; on a marathon-training article, it should describe the action (“runner lacing trail shoes at sunrise before a long run”). Context is what makes alt text useful instead of generic.
3. Weave in your keyword naturally — once
If the page’s target keyword genuinely describes the image, include it. A product page targeting “trail running shoes for beginners” can carry alt text like “blue trail running shoes for beginners on a rocky mountain path.” If the keyword does not fit, leave it out. Forced keywords read badly to humans and look spammy to algorithms.
4. Keep it under 125 characters
Most screen readers cut off alt text after roughly 125 characters. Longer descriptions get truncated mid-sentence, which is a worse experience than a shorter complete one. If an image needs more explanation (a data-heavy chart, for instance), summarize in the alt text and put the full detail in the surrounding paragraph or a data table.
5. Never start with “image of” or “picture of”
The <img> tag already tells assistive technology it is dealing with an image. “A picture of a cat” wastes seven characters announcing the obvious. Start with the subject: “Orange tabby cat sleeping in a sunbeam on a white windowsill.”
You now have the complete method for how to write alt text for SEO — let’s see it applied to ten realistic image types.
10 Before-and-After Alt Text Examples
Theory is cheap; examples stick. Here are ten realistic rewrites across common image types:
Work through all ten, and you will internalize how to write alt text for SEO faster than any checklist could teach you.
- Product photo
Before:alt="shoes"
After:alt="Blue trail running shoes with red laces, side view on white background" - Hero banner
Before:alt="banner"
After:alt="Smiling customer support team of four at desks with headsets, bright office" - Blog illustration
Before:alt="SEO graph"
After:alt="Line chart showing organic traffic doubling from January to June 2026" - Author headshot
Before:alt="photo"
After:alt="Portrait of Jane Smith, SEO strategist and author of this guide" - Infographic
Before:alt="infographic about email marketing"
After:alt="Infographic summarizing 5 email subject-line tactics with open-rate statistics"(full data lives in the article text) - Logo linking home
Before:alt="company logo"
After:alt="SSA Agency homepage"(linked images describe the destination, not the picture) - Button graphic
Before:alt="green button"
After:alt="Download the free SEO checklist"(functional images describe their function) - Screenshot
Before:alt="screenshot1"
After:alt="Google Search Console performance report filtered to image search clicks" - Team photo
Before:alt="our team"
After:alt="Six-person marketing team posing in front of the downtown office mural" - Decorative divider
Before:alt="fancy line decoration"
After:alt=""(purely decorative images get empty alt so screen readers skip them)
Study these rewrites and the pattern behind how to write alt text for SEO becomes obvious: name the specific subject, add one or two distinguishing details, and match the context of the page.
Special Cases: Decorative Images, Links, Charts, and Logos
The standard formula for how to write alt text for SEO flexes a little for edge cases. Here is how to handle each one correctly.
Decorative images (background swirls, divider flourishes, stock texture) should carry an empty alt attribute: alt="". This is different from omitting the attribute — empty alt tells screen readers to skip the image deliberately, while a missing attribute may cause them to read out the file name instead.
Images used as links change the job of the alt text. When an image sits inside an <a> tag, the alt text functions as the link’s anchor text. Describe where the link goes, not what the image shows: a logo linking to the homepage becomes “Acme Corp homepage,” and a product thumbnail linking to a category page becomes “Shop trail running shoes.”
Notice how the alt text job changes with context — internalizing this is what separates people who know how to write alt text for SEO from people who just fill in the field.
Complex charts and infographics cannot fit their data into 125 characters. Use the alt text for a one-sentence summary (“Bar chart comparing conversion rates across five landing page variants, with variant C leading at 8.2%”), then publish the full numbers as a table or paragraph next to the image. Everyone — sighted users, screen-reader users, and search engines — gets the complete picture.
Edge cases aside, the core of how to write alt text for SEO never changes: describe what you see, add page context, and keep it under 125 characters.
How to Find and Fix Missing Alt Text on Your Site
Knowing how to write alt text for SEO is only half the battle; most sites need a cleanup pass first. Here is a practical workflow:
Before you start the cleanup, remember that how to write alt text for SEO matters most on the pages that already drive your revenue and rankings.
Step 1: Crawl for missing alt attributes
A manual spot-check (right-click an image, Inspect, look at the alt attribute) works for one page. For a whole site, use a crawler: Screaming Frog SEO Spider’s free version flags every image missing alt text, and Ahrefs or Semrush site audits do the same. Export the list of URLs.
Step 2: Triage by page value
Do not start alphabetically. Fix images on your homepage, key service and product pages, and highest-traffic blog posts first. Then prioritize pages already ranking on page one or two for valuable keywords — a small relevance boost from better alt text can be the nudge that moves them up. E-commerce product pages come next: for shoppers using screen readers, alt text is the product description.
Step 3: Fix in bulk inside your CMS
In WordPress, every image in the Media Library has an “Alternative Text” field — fill it at upload time so you never create the problem again. For existing images, update the Media Library entries once and the alt text propagates everywhere the image is used. If your site was built with Elementor, pay special attention to hero sliders and background images, which are the most commonly forgotten spots.
Step 4: Measure in Search Console
After the fix-up, watch the Performance report in Google Search Console filtered by Search Type: Image. Rising image-search impressions over 4–8 weeks is the clearest signal your alt text work is paying off. Our image SEO optimization guide covers the compression and sizing half of this equation.
Run this cleanup once, and how to write alt text for SEO becomes a five-minute publishing habit instead of a dreaded backlog.
2026 Angles Most Alt Text Guides Miss
AI Overviews and AI search citations. Google’s AI Overviews and assistants like ChatGPT and Perplexity build answers from content they can understand. When an AI system needs to reference or describe a visual — a product comparison, a chart, a step-by-step photo — the alt text is the machine-readable caption it reaches for. Precise alt text makes your visuals citable in AI-generated answers, which is a brand-new visibility channel that did not exist when most alt text guides were written.
This is a genuinely new reason to master how to write alt text for SEO: well-described images can now earn citations inside AI-generated answers, not just image-search clicks.
Google Lens and visual search. Lens lets users search with their camera. Its understanding of an image on your site leans on the same textual signals as classic image search — file name, surrounding text, and alt text. If you sell products or publish visual how-tos, alt text is part of your Lens discoverability.
The filename-plus-alt combination. Competitors mention file names in passing, but few treat the pair as a system. Use them together: a descriptive file name (trail-running-shoes-blue-side-view.jpg) sets the topic, and the alt text delivers the human-readable description. Two aligned signals beat one.
Alt text and anchor text share a brain. Writing good alt text for linked images trains the same muscle as writing good internal link anchor text — in both cases you are describing a destination for someone (or something) that cannot see the picture. Sites that systematize one usually improve the other.
7 Alt Text Mistakes That Hurt Rankings and Users
- Keyword stuffing:
alt="running shoes best running shoes cheap running shoes buy running shoes"— terrible for screen-reader users and a long-standing spam signal. One natural keyword, maximum. - Leaving alt blank on meaningful images: every content image without alt is a missed accessibility and SEO signal.
- Describing decorative images:
alt="blue swirl decoration"clutters the screen-reader experience. Usealt="". - Duplicating surrounding text: if the caption already says “Q2 revenue by channel,” the alt text should not repeat it word for word — add the insight (“bar chart showing email overtaking paid search in Q2”).
- Letting WordPress auto-fill from file names: “IMG_4829-final-v2” as alt text is worse than useless. Disable auto-generation habits and write real descriptions.
- Writing a paragraph in the alt attribute: 300-character alt text gets truncated and annoys everyone. Summarize in alt; elaborate in the article.
- Forgetting linked images: a thumbnail linking to a product page with
alt="thumbnail"wastes anchor-text value. Describe the destination.
Avoid these seven errors and you are already ahead of most websites at how to write alt text for SEO.
Alt Text FAQ
Straight answers to the most common questions about how to write alt text for SEO.
Does alt text directly improve Google rankings?
Alt text is a confirmed relevance signal for image search and helps Google understand page content, but it is not a primary web-search ranking factor on its own. Think of it as removing a handicap rather than adding a superpower — pages with complete, accurate alt text compete at full strength.
How long should alt text be?
Aim for under 125 characters. That is the practical cutoff where most screen readers stop reading, and it forces the concision that makes alt text useful.
Should I put keywords in every image’s alt text?
No. Include your target keyword only where it genuinely describes the image — typically the lead image and product shots. Keyword-stuffed alt text hurts accessibility and can look manipulative.
What is the difference between alt text and image titles?
Alt text is read by screen readers and used by search engines; the title attribute only shows a hover tooltip and carries virtually no SEO weight. Always prioritize alt text.
Do background images need alt text?
CSS background images cannot carry alt attributes. If a background image conveys information, that information should also exist in the page text. Purely decorative backgrounds need nothing.
How do I add alt text in WordPress?
Open the Media Library, select the image, and fill in the “Alternative Text” field on the right. In the block editor, select the image block and use the “Alt text” field in the sidebar settings. For Elementor, select the image widget and fill the Alt Text field in the left panel.
That covers the mechanics — for the strategy behind each description, revisit the five-part formula for how to write alt text for SEO above before you write your next one.
Conclusion
Now you know how to write alt text for SEO: describe what you see in under 125 characters, add page context, include your keyword once where it fits, and leave decorative images empty. Then run the audit workflow — crawl, triage, fix, measure — so the knowledge turns into actual coverage across your site. Pair it with the technical half of the discipline in our image SEO guide and the on-page fundamentals in our heading tags guide, and check our e-commerce SEO checklist if product images are your revenue engine. Small attribute, outsized return — start with your ten most important pages today.
One more resource worth bookmarking alongside this guide to how to write alt text for SEO: the W3C’s image accessibility tutorial covers the accessibility side in depth.