Skip to main content

ADA Title II|WCAG 2.1 AA required by April 26, 2027 (50,000+) and April 26, 2028 (smaller entities, special districts)

Free tool · runs in your browser

Alt text helper

Two parts: a short decision tree that tells you what kind of alt text an image needs (or none), and a checker that flags common mistakes in what you wrote.

Part 1

Does this image need alt text?

Part 2

Check your alt text

    Examples from school and city websites

    ImageWeak alt textBetter
    District logo linking to homelogo.pngSpringfield School District home
    Photo of students at a science fair, next to a news story about itImage of kidsFifth graders explain their water filter project to judges
    Decorative wave graphic between sections(alt missing)alt="" (empty)
    Flyer for a public hearing posted as a JPGFlyerPublic hearing notice (details are in the text below), and the date, time and place typed on the page
    Magnifying glass icon on the search buttonmagnifying glassSearch
    Chart of the budget by departmentChartPie chart of the 2026 budget by department; the full figures are in the table below

    Where alt text goes wrong in content management systems

    • The file name is filled in automatically. Many CMSs copy the file name into the alt field. Check new uploads.
    • The same alt is reused everywhere. The media library stores one alt per image, but the right alt depends on where it is used.
    • Slideshows and news cards often have an image and a headline in the same link. Give the image alt="" so the headline is not read twice.

    An automated scan finds missing alt attributes and file-name alt text across every page. It cannot judge whether alt text is good; that takes a person. Run a free scan to find the images with no alt at all.

    Sources

    1. W3C WAI, An alt decision tree
    2. W3C WAI, Images tutorial
    3. W3C, Understanding 1.1.1 Non-text Content
    4. WebAIM, Alternative text

    Questions

    Frequently asked

    What is alt text?

    Alt text is the text alternative for an image, written in the alt attribute of the img element. Screen readers read it aloud, and browsers show it when the image does not load. WCAG 1.1.1 requires a text alternative for every meaningful image.

    How long should alt text be?

    As short as it can be while still conveying the purpose, usually one sentence or less. There is no fixed limit in WCAG; about 150 characters is a practical guide. Complex images such as charts need a longer description in the page text.

    Should decorative images have alt text?

    They should have an empty alt attribute (alt=""), which tells screen readers to skip them. Leaving the attribute out entirely is a failure, because many screen readers then read the file name.

    Should alt text start with "image of"?

    No. Screen readers already announce that the element is an image. Start with the subject. "Photo of" can be useful when the type of image matters, for example a historical photograph.

    Does alt text help SEO?

    Search engines use alt text to understand images, so good alt text helps image search. Write it for people, not for keywords; stuffing keywords makes it worse for screen reader users and can be treated as spam.

    What about images of flyers and announcements?

    A flyer posted as an image is one of the most common barriers on school and city websites. Put the event details on the page as real text, and give the image a short alt. WCAG 1.4.5 also asks you to use real text instead of images of text.