Why is 125 characters the recommended limit?

Early screen readers had a 125-character buffer and would truncate longer alt text. Modern readers handle longer strings, but the limit remains a practical guideline because very long descriptions are disruptive to the listening experience. WCAG itself does not set a hard numeric limit, but 125 characters is the broadly accepted best practice.

Should decorative images have alt text?

No. Purely decorative images should have an empty alt attribute (alt="") so screen readers skip them entirely. Adding alt text to a decorative image forces screen reader users to listen to unnecessary information.

What makes a good alt text description?

Good alt text is concise, describes the content and function of the image, avoids phrases like "image of" or "picture of," and does not repeat nearby caption text. For complex charts, a brief summary in alt text plus a longer description in the page body is preferred.

Does this tool send my text anywhere?

No. All processing happens entirely in your browser. Your alt text is never sent to any server.

Is 125 characters a hard WCAG rule?

No. WCAG 2.1 Success Criterion 1.1.1 requires that non-text content has a text alternative, but does not specify a character limit. The 125-character figure is a widely adopted practical guideline, not a strict compliance requirement.

Alt Text Length Checker

Name: Alt Text Length Checker
Availability: InStock
Author: Nham Vu

Paste your image alt text and instantly see character count, compliance status, and actionable quality tips.

Your Alt Text

Max recommended: 125 characters 0 / 125

Quality Checks

Enter alt text to see quality feedback

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Summary

Paste your image alt text and instantly see character count, compliance status, and actionable quality tips.

How it works

Type or paste your image alt text into the input field.
The character counter updates live as you type.
A color-coded status bar shows whether you are within the 125-character guideline.
Quality checks flag common issues like placeholder text, file names, or redundant phrases.
Use the feedback panel to refine your alt text until all checks pass.

Use cases

Audit alt text for images before publishing a web page.
Train content authors on accessible image descriptions.
Quickly verify CMS-generated or AI-written alt text meets WCAG guidance.
Batch-check alt text snippets copied from a spreadsheet or CMS export.
Catch placeholder values like "image.png" or "image of" before they reach production.
Educate developers on the reasoning behind the 125-character recommendation.

Frequently Asked Questions

Last updated: 2026-07-01 · Reviewed by Nham Vu