What it does
The alt text helper counts your description against X's 1,000-character limit and flags common problems: starting with 'image of', hashtags, handles, links, all caps, emoji and missing text from the image.
What makes good alt text?
Good alt text tells someone who can't see the image what they need to know to understand the post. That means the point of the image, not every pixel. A screenshot of a tweet-length quote needs the quote; a holiday photo needs the scene and the mood; a chart needs the trend and the key numbers.
| Image | Weak | Better |
|---|---|---|
| Chart | "Graph." | "Line chart of weekly sign-ups, rising from 120 in March to 410 in June." |
| Quote card | "Quote image." | "Quote card: 'Ship small, ship often.' White text on a dark blue background." |
| Product photo | "Image of our new mug." | "Matte black 12 oz mug with an orange handle, on a wooden desk next to a laptop." |
| Reaction GIF | "Funny GIF." | "A cat slowly pushes a glass off the table while staring at the camera." |
What does the checker look for?
- Length: over 1,000 characters is an error; under four words gets a nudge.
- "Image of…": screen readers already announce an image, so start with what it shows.
- Hashtags, handles and links: read out awkwardly and can't be tapped.
- All caps and emoji: may be read letter by letter or by long emoji names.
- Text in the image: tick the box and you'll be reminded to include it.
The checks are guidance, not rules. If you have a good reason to break one, do.
How do I add it on X?
Attach the image in X's composer, then tap the image or its ALT label and paste your description. Each image in a post gets its own. The alt text guide walks through it step by step.
FAQ
How long can alt text be on X?
Up to 1,000 characters per image, according to X's Help Center. Most good descriptions are one to three sentences.
Where do I add it on X?
After attaching an image in X's composer, tap the image and look for the option to add a description (often labelled ALT or 'Add description'). Paste your text there.
Do GIFs and videos need it too?
GIFs, yes: describe the action and the joke. For videos, captions matter more; a short description still helps people who can't play the video.