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Alt Text Best Practices Guide

Learn how to write effective alt text that improves accessibility and SEO. Want to improve your content writing? Check out ReachWriter for AI-powered content creation and score readability in seconds with ReadabilityPro.

What Makes Good Alt Text?

Good alt text serves two purposes: it helps screen reader users understand your images, and it provides context for search engines. The best alt text is:

Descriptive:Clearly describes what's in the image
Concise:Typically under 125 characters (screen reader limit)
Contextual:Relevant to the page content and purpose
Meaningful:Adds value for users who can't see the image
Natural:Sounds like normal human language, not keyword stuffing

Do's and Don'ts

Do's

  • ✓Be specific and descriptive
  • ✓Include relevant details (colors, people, actions)
  • ✓Match the image's purpose on the page
  • ✓Keep it under 125 characters when possible
  • ✓Use decorative images with empty alt (alt="")
  • ✓Include text visible in the image if important

Don'ts

  • ✗Start with "image of" or "picture of"
  • ✗Stuff keywords for SEO
  • ✗Leave alt text empty on meaningful images
  • ✗Use file names (IMG_1234.jpg)
  • ✗Write novels (keep it concise)
  • ✗Repeat surrounding text content

Examples

Bad
alt="business meeting"
Good
alt="Five diverse professionals collaborating around a conference table reviewing marketing charts"
Bad
alt="product.jpg"
Good
alt="Blue wireless headphones with noise cancellation and folding design"

Decorative Image (border, icon, etc.):

Correct
alt=""

Empty alt tells screen readers to skip decorative images

E-commerce Product:

Bad
alt="running shoes"
Good
alt="Nike Air Zoom Pegasus 40 men's running shoes in black and white"

Blog Post Photo:

Bad
alt="recipe image"
Good
alt="Freshly baked chocolate chip cookies on cooling rack with melted chocolate chips visible"

Social Media Post:

Bad
alt="sunset photo"
Good
alt="Orange and pink sunset over mountain peaks with silhouetted pine trees in foreground"

Documentation Screenshot:

Bad
alt="screenshot"
Good
alt="Settings menu showing Enable Notifications toggle switch in the on position"

Infographic with Data:

Bad
alt="statistics"
Good
alt="Bar chart showing website traffic increased 45% in Q4 2024 from 10K to 14.5K monthly visitors"

WCAG 2.1 Accessibility Guidelines

The Web Content Accessibility Guidelines (WCAG) provide standards for accessible web content. For images:

Level A (Required):All non-decorative images must have alt text
Decorative Images:Use empty alt (alt="") to indicate the image is purely decorative
Complex Images:Provide longer descriptions using aria-describedby or longdesc when needed
Text in Images:Avoid using images of text; if unavoidable, include the text in alt attribute
Functional Images:Describe the function/action, not the image itself (e.g., "Search" not "Magnifying glass icon")

Alt Text for SEO

Alt text helps search engines understand your images and can improve your SEO:

1
Include Target Keywords Naturally:Use relevant keywords, but don't force them
2
Be Descriptive:Detailed descriptions help Google Images index your content
3
Context Matters:Match alt text to the page topic and surrounding content
4
Avoid Keyword Stuffing:Google penalizes unnatural keyword repetition
5
File Names Also Matter:Use descriptive file names like "blue-wireless-headphones.jpg"

Balance is Key

Good alt text serves both accessibility AND SEO. Prioritize users first, search engines second.

Common Mistakes to Avoid

1 1. Keyword Stuffing

Bad

"Buy blue headphones best headphones wireless headphones sale discount"

Good

"Blue wireless headphones with noise cancellation"

2 2. Being Too Vague

Bad

"A person"

Good

"Woman smiling while working on laptop at coffee shop"

3 3. Repeating Context

Bad

"Adding "Image of a blue car" when the caption already says "Our new blue car model""

Good

"Add unique details like "Sleek sedan with chrome accents parked in showroom""

4 4. Using "Image of" or "Picture of"

Bad

"Image of a sunset over the ocean"

Good

"Sunset over calm ocean with orange and purple sky"

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