Image Alt Text Checker - Free Online Scanner

This image alt text checker scans any public webpage and lists every image that has a missing alt attribute, an empty one, or a text description. It is built for SEOs, developers, content editors and accessibility reviewers who need a quick audit. Paste a URL and you get counts, a coverage percentage and an image-by-image table.

What Is Image Alt Text?

Image alt text is the value of the alt attribute on an HTML image element. It describes the image in words, so people using screen readers, browsers that fail to load the file, and search engines can understand what the image shows.

An image can be in one of three states, and the difference matters:

• Missing alt attribute: the image tag has no alt attribute at all. Screen readers may read out the file name instead, and search engines get no description. This is the state to fix first.
• Empty alt attribute: the attribute exists but has no text. This is correct for purely decorative images such as dividers, background flourishes or icons that repeat nearby text, because it tells assistive technology to skip them.
• Alt text present: the attribute contains a description, such as "Red trail running shoes on a wet rock".

Google's Search Central documentation advises using descriptive, useful alt text that fits the page's content. W3C accessibility guidance treats a missing alt attribute as an error for informative images. Alt text also doubles as the fallback text when a file fails to load, and it helps Google Images understand what a picture is about.

How to Use the Image Alt Text Checker

You only need the address of a live page. The whole check takes a few seconds for a typical page.

1. Copy the full address of the page you want to audit, including https://.
2. Paste it into the field that shows the https://example.com/page placeholder.
3. Press Check Images. The button changes to Scanning while the page is read.
4. Look at the summary: Total Images, Has Alt Text, Missing Alt, Empty Alt (decorative) and Alt Text Coverage.
5. Open the Missing Alt tab to see the source address of every image with no alt attribute.
6. Open the All Images tab to see each image's file name, its alt text and a status of Good, Missing or Empty.
7. Fix the images in your CMS or template, then run the same URL again to confirm the numbers changed.

If the URL is not valid or the page cannot be reached, you see a short error message instead of results. Check for typos and make sure the page is public.

Worked Example: Reading a Real Result

Say you scan a blog post at https://example.com/blog/trail-running-shoes and the summary shows 20 total images, 14 with alt text, 4 missing and 2 empty.

The coverage figure is the number of images with alt text divided by total images: 14 / 20 = 70%. The four missing images are your to-do list, and the Missing Alt tab shows their source addresses so you can find them in the page.

The two empty images are not errors if they are decorative, such as a divider line and a background swirl. They do pull the percentage down, because only images with text count as covered. Excluding them, your effective coverage is 14 / 18, or about 78%. After you add descriptions to the four missing images and re-scan, the result should read 18 with alt text, 0 missing and 2 empty, which is 90% coverage with every remaining gap intentional.

How Do You Read the Results and Fix Problems?

Each number tells you a different thing, and each status has a specific fix. Use this table as a quick guide.

What a good result looks like

A healthy page has zero images in the Missing Alt tab. Every empty image should be one you can justify as decorative. A coverage score near 100% is the goal on pages that contain mostly content images, such as product pages and articles.

What a poor result looks like

A long Missing Alt list usually points to a template or plugin problem, not a one-off mistake. If the same logo, icon or badge shows up on every page, fix it once in the theme. If dozens of product photos are missing alt text, look at the upload settings in your CMS, where you can often add a rule that fills alt text from the product name.

A note on the Good label

The Good status means text is present. It does not judge quality. An alt value like "image1" or "IMG_2043.jpg" still shows as Good, so scan the Alt Text column yourself and look for filler, file names and repeated keywords.

Who Should Use an Image Alt Text Checker?

Anyone responsible for how a page is found or used benefits from a quick alt text audit. These are the most common situations:

• SEO audits: check key landing pages and blog posts for missing image descriptions before you start deeper optimization.
• Accessibility reviews: confirm that informative images have descriptions so screen reader users do not hit silent or confusing gaps.
• Content publishing: run a page after an editor uploads photos to catch images added without alt text.
• Ecommerce and WordPress, Shopify or Squarespace sites: verify product galleries and theme images, which are often added in bulk and skipped.
• Site migrations and redesigns: compare a page before and after launch to make sure a new template did not strip alt attributes.

For a wider review, the Website Audit and Performance tools cover other technical checks you can run on the same page.

Best Practices, Common Mistakes and Troubleshooting

Good alt text is short, specific and written for a person who cannot see the image. A widely used guideline is to keep it to about 125 characters or fewer, since some screen readers cut off longer values.

Write useful descriptions

• Describe what matters in context. "Woman tying a trail running shoe" beats "shoes".
• Include a keyword only when it truly describes the image. Forcing "best running shoes cheap running shoes" into every image can hurt readability.
• Skip "image of" and "picture of". Screen readers already announce an image.
• For linked images, describe where the link goes, such as "Download the 2024 sizing chart".
• For images that contain text, such as a banner or infographic, include that text in the alt value. If you need to pull the words out of a picture first, the image to text OCR tool can help.

Mistakes to avoid

• Leaving the attribute off entirely when you meant to mark an image as decorative. Use an empty alt instead.
• Using the same description for every image in a gallery.
• Putting a file name or a dash in the alt field to make a warning disappear.

Troubleshooting a surprising result

• Zero images found: the page may load its pictures with scripts after the page opens, or it may use CSS backgrounds. Neither shows up as an image tag in the original page code.
• Count differs from what you see: logos, tracking pixels and tiny icons count as images too. Open All Images to see them by file name.
• Error message on a valid page: confirm the URL works in a browser and does not need a login. If you suspect the page is failing, a bulk HTTP status checker can confirm it returns a normal response.
• Fixed but still showing as missing: clear your site cache or CDN, then scan again, because you may be seeing an older copy of the page.

Limitations to Keep in Mind

This tool checks one URL at a time and reports on image tags it finds in the page's HTML. It does not judge whether alt text is accurate, relevant or well written, and it does not check CSS background images, which have no alt attribute. Images inserted only after scripts run may not be listed.

Treat the coverage percentage as a starting point, not a pass or fail grade. Empty alt attributes lower the figure even when they are correct, so always read the Empty count alongside it. For a fuller picture of page quality, pair this scan with a code to text ratio check and a GZIP compression check, since heavy pages with many images can load slowly.

Run the image alt text checker on your most important page now, fix everything in the Missing Alt tab, and scan again to confirm your coverage went up. Then repeat the process on your next-highest-traffic pages.