The Power of Alt Text: Why It Matters for SEO, Accessibility & User Experience
When marketers talk about SEO, the conversation usually centers around keywords, backlinks, and meta descriptions. Yet, one powerful element is often overlooked: alt text.
Alt text—short for alternative text—does far more than assist screen readers. It helps search engines understand your images, improves your visibility in image search, and enhances user experience when visuals fail to load. In this guide, we’ll dive into why alt text is crucial for SEO and how to use it effectively.
What Is Alt Text?
Alt text is an HTML attribute that describes the content of an image. Originally created to make the web more accessible to visually impaired users, it now also plays a key role in search engine optimisation.
Alt text serves three core purposes:
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Accessibility: Helps screen readers describe images to blind or visually impaired users.
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SEO: Enables search engines to understand and index images, boosting your site’s visibility.
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User Experience: Displays descriptions when images don’t load, maintaining content clarity.
Why Alt Text Is Important for SEO
1. Improves Search Engine Understanding
Search engines can’t interpret images visually—they rely on text-based signals like alt text to determine relevance. Optimised alt tags:
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Describe the image content clearly and concisely
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Include relevant keywords (when appropriate)
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Help search engines understand the page’s topic more comprehensively
2. Boosts Image Search Rankings
Google Images is a major driver of organic traffic. With alt text, your images are more likely to appear in image search results, increasing click-through opportunities and site visibility.
3. Enhances Overall Page SEO
Alt text contributes to your page’s semantic relevance, reinforcing keyword themes and supporting Google’s ranking algorithms across both image and traditional search.
Alt Text and User Experience
Alt text does more than support SEO—it’s key to an inclusive and user-friendly web.
1. Accessibility for All Users
Screen readers use alt text to describe visual content to users with visual impairments. Without it, important information in images is lost.
2. Fallback for Broken Images
If an image fails to load, the alt text is displayed in its place—ensuring users still understand the content or message.
3. Additional Context
Even when images load properly, alt text can clarify complex visuals like infographics or charts, aiding comprehension for all users.
Benefits of Alt Text for SEO & Traffic Growth
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Increased organic traffic from both web and image searches
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Lower bounce rates by improving engagement and user satisfaction
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Better click-through rates (CTR) in image search results
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Enhanced E-A-T (Expertise, Authoritativeness, Trustworthiness) by supporting accessibility
Best Practices for Writing Alt Text
To write effective alt text, follow these SEO and accessibility guidelines:
✔ Be Descriptive and Concise
Aim for under 125 characters, clearly describing the image’s purpose.
✅ Good:
“Golden retriever puppy playing with a red ball in a park”
❌ Bad:
“Dog” (too vague)
“Cute golden retriever playing outdoors on a sunny day in the park with grass” (too long)
✔ Use Keywords Naturally
Include relevant keywords only when they fit organically. Avoid keyword stuffing.
✅ Good:
“Freshly baked chocolate chip cookies on a cooling rack”
❌ Bad:
“Best chocolate cookie bake recipe dessert quick snack 2024”
✔ Skip Redundant Phrases
Don’t start alt text with “Image of…”—screen readers already indicate it's an image.
✅ Good:
“Woman hiking along a mountain trail at sunset”
❌ Bad:
“Image of a woman hiking…”
✔ Describe Functional Images
For icons or buttons, explain what they do:
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“Search button”
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“Download brochure (PDF)”
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“Company logo: GreenLeaf Wellness”
✔ Leave Decorative Images Empty
For visuals that don’t convey meaningful content, use an empty alt attribute:
alt=""
This tells screen readers to ignore them.
✔ Tailor Descriptions to Context
Ask: “What information would a blind user need to understand this image?”
For infographics or charts, summarise the key takeaways:
Example:
“Pie chart showing mobile OS market share: Android 72%, iOS 27%, others 1%”
Alt Text Do’s & Don’ts
| ✅ Do This | ❌ Avoid This |
|---|---|
| “Vintage camera on wooden desk” | “Camera” |
| “Chef slicing sushi rolls” | “Food” |
| “Twitter share button” | “Click here” |
| “Map showing Austin bike trails” | “Map” |
Alt Text Helps More Than Just SEO and Accessibility
1. Image Load Failures
Slow connections or broken links? Alt text keeps your content readable.
2. Clarifies Complex Images
Alt text acts like a caption for infographics or memes, helping users interpret visuals.
3. Supports Non-Native Speakers
Clear alt text aids comprehension for users unfamiliar with cultural references or sarcasm.
4. Improves Social Sharing
Platforms like LinkedIn or email clients sometimes display alt text when images don’t load.
5. Helps Users with Cognitive Disabilities
Alt text offers an alternative way to process visual content through text.
How to Add Alt Text in Popular CMS Platforms
WordPress (Block Editor)
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Select your image.
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In the sidebar, locate the “Alt Text” field.
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Enter your description.
Shopify
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Go to Products > Select a product.
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Click on the image > Add alt text in the “Alt text” field.
Wix
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Click the image > “Settings” > “Alt Text”.
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Enter your description.
Squarespace
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Click image > “Edit” > “Alt Text”.
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Add description and save.
Joomla
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Click the image in the editor > “Edit” > Fill in the “Alternative Text” field.
FAQs About Alt Text
Q1: What’s the optimal format for alt text?
A clear, concise description that provides context without keyword stuffing.
Q2: Is there a character limit?
Stick to around 125 characters to ensure screen reader compatibility.
Q3: Is alt text a ranking factor?
Yes—especially for image search, and it contributes to overall page relevance.
Q4: Alt text vs. image description?
Alt text is for screen readers and SEO; image descriptions are for all users and typically more detailed.
Q5: Should decorative images have alt text?
No. Use alt="" to keep screen readers focused on relevant content.
Q6: Can I reuse the same alt text?
Only if the images are identical. Otherwise, tailor each alt tag to the specific image.
Q7: How do I test my alt text?
Use tools like Google Lighthouse, WAVE, or test with screen readers like NVDA or VoiceOver.
Final Thoughts
Alt text is more than a technical requirement—it’s a strategic tool. When written well, it improves:
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Search visibility
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User experience
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Accessibility
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Site authority
Pro Tip:
Run an image audit using SEO tools like Screaming Frog or Google Lighthouse. Updating or adding missing alt tags can have a measurable impact on traffic and engagement.
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