How long should alt text be?

Five to fifteen words handles most photographs comfortably. Anything shorter feels uninformative, while longer descriptions become tedious to listen to through a screen reader. Calibrate length to importance, with decorative images taking empty alt, logos getting something like 'Acme Inc. logo', and detailed photos earning a short descriptive sentence.

What separates good alt text from bad?

Strong descriptions are specific, contextually relevant, free of redundant lead-ins like 'image of', appropriately sized, and include any meaningful text the image contains. Weak descriptions tend to be generic, missing entirely, stuffed with keywords, or padded with redundancy. The checker grades against both patterns.

What about decorative images?

Pure decoration like a page divider, ornamental icon, or background flourish carries no information. The right move is empty alt as alt="" so the screen reader skips it. Writing alt="decorative" is the worst choice because it interrupts the listener without conveying anything useful.

Should I lead with 'image of' or 'photo of'?

No. Assistive technology already announces that the element is an image or graphic, so 'image of dog' becomes 'image image of dog' to a screen reader user. Just describe what is shown, like 'Dog playing fetch on a beach'.

How does alt text interact with SEO?

Search engines pull signals from alt attributes when ranking images and understanding page content. Natural descriptive language improves visibility while obvious keyword stuffing gets penalized. The best approach uses relevant keywords organically inside genuine descriptions rather than gaming the attribute.

Does this apply to every image?

All meaningful images need alt text, while purely decorative ones take empty alt. Most icons carry meaning, like a warning or success indicator, and functional images such as button graphics need descriptions of the action they represent. When in doubt, provide alt rather than skip it.

Is the data sent to a server?

No. The analysis runs as plain JavaScript text processing in your browser, so your alt text never leaves your device.

Alt Text Quality Checker

Analyze image alt text for accessibility best practices. Get scoring, improvement suggestions, and WCAG compliance tips. Free alt text tool.

Web & SEO

Instant results

Enter alt text to analyze

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WCAG 2.1 Alt Text Guidelines

SC 1.1.1 Non-text Content (Level A): All non-text content must have a text alternative that serves the equivalent purpose.

Best Practices:

Be specific and descriptive — describe what the image shows and why it matters
Keep it concise — aim for under 125 characters (screen readers may truncate longer text)
Do not start with "image of" or "picture of" — screen readers already announce it as an image
Do not include file names or extensions — describe content, not technical details
Consider the image's context — the same image may need different alt text on different pages
Use empty alt (alt="") for purely decorative images that add no information
For complex images (charts, infographics), provide a brief alt and a longer description nearby

How to Use Alt Text Quality Checker

Paste your alt text

Drop in the candidate description, whether it came straight from an HTML alt attribute or you are drafting fresh.

Review the quality analysis

The checker grades length, specificity, redundant lead-ins, and decorative classification, then surfaces a score alongside concrete improvement suggestions.

Apply the improvements

Tighten generic language, drop redundant phrases like 'image of', and adjust length to match how much the image actually conveys.

Verify with a real screen reader

Test the final version through NVDA, JAWS, or VoiceOver to hear what users actually experience. Automated analysis catches the obvious issues, while listening through real assistive tech catches the rest.

When to Use Alt Text Quality Checker

Accessibility compliance

Screen readers read alt text aloud, search engines parse it for context, and browsers display it when an image fails to load. The checker grades a draft against length, specificity, redundancy, and decorative-versus-informative classification so accessibility teams can ship WCAG-compliant content with confidence.

SEO optimization

Google Image Search and general page ranking both pull signals from alt attributes. Strong descriptions improve image-search visibility and accessibility audits at the same time, which is why marketers and SEO writers run their captions through the checker before publishing.

Content audit and improvement

Older sites often inherit alt text that was auto-generated, copy-pasted from filenames, or simply missing. Agencies running accessibility audits use the checker to scan existing inventory and surface the lowest-quality entries for rewriting first.

Educational training

Showing writers what good and bad alt text actually look like teaches faster than abstract guidelines. Trainers and content teams use the checker as a hands-on lab where students paste candidates and watch the score change as they iterate.

Alt Text Quality Checker Examples

Quality alt text

Input

Photo of a golden retriever puppy playing fetch

Output

An excellent grade because the description is specific, runs about eight words, and conveys subject, breed, and action together

Strong alt text names the subject, includes a meaningful detail like breed or color, and captures what is happening. The five-to-fifteen-word range hits the sweet spot for most photographs.

Generic alt text

Input

image of dog

Output

A poor grade flagged for being vague and for using the redundant phrase image of

Screen readers already announce that an element is an image, so leading with image of wastes a syllable. Worse, dog tells the user almost nothing about what the picture actually shows.

Decorative image flag

Input

A purely ornamental page divider

Output

A recommendation to use alt="" so screen readers skip the element entirely

Decorative graphics carry no information, and announcing them only adds noise. Empty alt is the correct value here, while writing alt="decorative image" is the worst of both worlds because it interrupts the reader without conveying anything.

Tips & Best Practices for Alt Text Quality Checker

1.Specificity beats generic labels every time. Golden retriever puppy reads better than dog, and snow-capped mountain at sunset reads better than mountain.
2.Drop the phrases image of, picture of, and photo of. Assistive technology already declares the element type, so repeating it just wastes the listener's attention.
3.Calibrate length to importance. A logo can get away with Acme Inc. company logo while a detailed infographic deserves a longer caption that captures the key data points.
4.When an image contains text, that text belongs in the alt attribute. A photograph of a stop sign should include the word stop so screen-reader users do not lose the message.
5.Decide between decorative and informative deliberately. Pure decoration takes alt="" while anything that carries meaning gets a description; writing alt="decorative" is incorrect because it announces something with zero value.
6.Resist the urge to stuff keywords. Search engines penalize obvious manipulation, and natural descriptive language serves both SEO and accessibility goals better than a list of search terms.

Frequently Asked Questions

Three audiences depend on it. Screen readers describe images aloud to blind and low-vision users, search engines parse alt text to understand image content, and browsers fall back to it when an image fails to load. Strong alt text covers WCAG compliance, inclusive design, and search visibility all at once.

Alt Text Quality Checker

WCAG 2.1 Alt Text Guidelines

How to Use Alt Text Quality Checker

Paste your alt text

Review the quality analysis

Apply the improvements

Verify with a real screen reader

When to Use Alt Text Quality Checker

Accessibility compliance

SEO optimization

Content audit and improvement

Educational training

Alt Text Quality Checker Examples

Quality alt text

Generic alt text

Decorative image flag

Tips & Best Practices for Alt Text Quality Checker

Frequently Asked Questions

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