100, 150, or 200? Debunking the Alt text character limit

"There's a random myth that flies around in Accessibility that alt text is limited to 100, 150 or 200 characters long. It seems to be one of those things that's been cited in multiple places but...this isn't true. Screen readers, often used by people who are blind or have low vision, will read the alt text to describe the image, making web content accessible."

"There is no hard limit or rule for alt text, no threshold and no advantage linked to those numbers. It's a bit unclear where this has come from and been cited in many places, perpetrated as fact. The ideal length is determined by context, purpose, and content. It should be as long as it needs to be to clearly convey the image's meaning."

No hard limit exists for alt text length. Screen readers used by people who are blind or have low vision will read full alt text to describe images, so alt text functions as the image content. Myths claiming 100, 150, or 200 character limits are false and can force writers to omit crucial details. Arbitrary restrictions appear in CMS fields, social platforms, and input components, blocking adequate descriptions. Automated accessibility testing tools and some platforms may incorrectly flag longer alt text as errors. Large language models can amplify the myth to newcomers. Alt text should be succinct, accurate, and as long as necessary to convey meaning.

Read at Chrisyoong