Image Alt Text Checker
Paste your page HTML to instantly find every image that is missing alt text, uses an empty alt attribute, or has a low-quality description like a file name. Alt text is WCAG 2.2 Success Criterion 1.1.1 — and one of the most common triggers in ADA website lawsuits.
In your browser, right-click the page → “View Page Source” (or press Ctrl/Cmd + U), copy it, and paste it below. Everything is analyzed locally in your browser — nothing is uploaded.
Writing Good Alt Text for WCAG 1.1.1
Alternative text (“alt text”) is the short written description that screen readers announce in place of an image, and that browsers show when an image fails to load. WCAG 2.2 Success Criterion 1.1.1 (Non-text Content, Level A) requires a text alternative for every image that conveys information. Getting it right is one of the highest-impact accessibility improvements you can make, because images without text alternatives are completely invisible to blind and low-vision users.
Informative images
Photos, product shots, and diagrams that convey meaning need alt text that describes their content and purpose — for example, “Freshly baked butter croissant on a wooden board”, not “croissant.jpg”.
Decorative images
Spacers, background flourishes, and images fully described by adjacent text should use an empty alt="" so screen readers skip them. A missingalt attribute is not the same — it can cause the file name to be read aloud.
Functional images
An image that is also a link or button (such as a logo linking home, or an icon-only button) must have alt text describing its action — e.g. “Search” — not its appearance.
Keep it concise
Aim for roughly 125 characters or fewer. For complex images like charts, put the short summary in alt text and the full detail in a caption or the surrounding content.
What this tool checks — and what it can’t
This checker parses the HTML you paste and evaluates every <img>, image map area, and image button. It flags missing alt attributes, empty alt values, likely file names, redundant phrases like “image of”, placeholder text, and overly long descriptions. It also recognizes valid alternatives supplied via aria-label and role="presentation". What no automated tool can do is judge whether a description is accurate and meaningful— that always needs a human. Automated scanning reliably covers about 30–40% of WCAG success criteria; the rest require manual review.
Frequently Asked Questions
What WCAG rule does alt text satisfy?
Alt text satisfies WCAG 2.2 Success Criterion 1.1.1 Non-text Content (Level A). It requires that all non-text content — including images — has a text alternative that serves an equivalent purpose, so people using screen readers or with images disabled can still access the information.
When should alt text be empty?
Use an empty alt attribute (alt="") for purely decorative images — spacers, background flourishes, or images duplicated by adjacent text. An empty alt tells screen readers to skip the image. This is different from a missing alt attribute, where screen readers may read out the image file name instead.
Why is missing alt text a legal risk?
Missing alt text is one of the most frequently cited violations in ADA website accessibility lawsuits, which reached 3,117 federal filings in 2025 (UsableNet). Because screen reader users cannot perceive an image without a text alternative, courts and the DOJ treat images without alt text as a barrier to access under the ADA.
How long should alt text be?
Aim for roughly 125 characters or fewer. Alt text should convey the meaning and purpose of the image concisely. If an image needs a longer explanation — such as a chart or infographic — describe it in a caption or adjacent body text rather than cramming everything into the alt attribute.
Does this tool upload my HTML anywhere?
No. The alt text checker parses and analyzes your HTML entirely in your browser using the built-in HTML parser. Nothing you paste is sent to a server. To scan a live URL and every page on your site automatically, use the CompliaScan site scanner.
Can automated tools verify that alt text is accurate?
No. Automated checks can confirm that an alt attribute exists and flag likely-poor values like file names or redundant phrases such as “image of”. They cannot judge whether the description accurately represents the image — that always requires human review. Automated scanning reliably covers roughly 30–40% of WCAG success criteria.
Check Every Image on Your Whole Site
Checking one page at a time by hand? Our automated scanner crawls your pages and tests every image for missing alt text — plus contrast, form labels, keyboard traps, and 100+ more WCAG 2.2 checks. Free scan, no signup required.
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