Image Alt Text Generator — Free, WCAG-Compliant
Upload any image and get accurate, WCAG-compliant alt text in seconds. Improve accessibility, SEO, and screen reader compatibility instantly.
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Real Examples You Can Copy
Alt Text Examples — Good vs Generic
"A white ceramic coffee mug with a minimalist black mountain silhouette design sits on a warm wooden table surface against a soft grey background, with morning light from the left side"
"A young woman in a red coat walks along a cobblestone street in a European city on a rainy evening, with reflections in the wet pavement and warm cafe lights in the background"
"Five diverse professionals in business casual attire collaborate around a glass conference table with laptops and documents, in a bright modern office with floor-to-ceiling windows"
How to Use This Tool
Image to alt text in 3 steps
Why it works
Why good alt text matters — and why this produces it
Bad alt text says 'image of dog'. Good alt text describes what is shown and why it matters.
Part of the image tools suite — also see the full image description tool.
WCAG-compliant alt text describes what is shown and why it matters — not just what objects appear. Output works for screen readers and SEO.
For accessibility audits and ongoing alt-text remediation on sites where the image library is large enough that hand-writing every alt attribute is not realistic. The output follows WCAG 2.1 conventions; the human reviewer’s job becomes editing for accuracy rather than starting from scratch.
FAQ
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How to write alt text that actually helps
Alt text is one of the few places on the web where a single sentence has both a legal compliance role and a real-user accessibility role at the same time. Auto-generated alt text gets the descriptive layer right most of the time, but the difference between “technically compliant” and “actually useful” is where almost all the editing happens. Below is a short editorial primer on what good alt text looks like, what AI handles well, and where the human reviewer’s judgement still matters.
What WCAG actually requires
The rule that governs alt text is WCAG 2.1 Success Criterion 1.1.1 Non-text Content, which has been the baseline for accessibility compliance in most jurisdictions since 2018. It says non-text content needs a text alternative that “serves the equivalent purpose.” That phrase is doing a lot of work — equivalent purpose, not equivalent description.
This is the difference between literal and functional alt text. A photo of a CEO speaking on stage might be literally described as “A man in a navy suit speaking at a podium with a blue backdrop.” That is accurate but not equivalent. The equivalent text depends on why the image is on the page: if it is illustrating a news article about the speech, alt text might be “CEO Jane Smith announcing the company’s 2026 product roadmap.” If it is on a press kit page, alt text might just be “Photo of Jane Smith.” Same image, different alt text, both compliant.
The implication: AI cannot fully solve alt text by itself, because it does not know the page context the image is in. It produces accurate descriptions; the human reviewer adds the contextual layer that makes the description equivalent.
What AI alt text gets right and wrong
After running a vision-language model across a few hundred images, a clear pattern emerges in what works first-pass and what consistently needs editing.
Reliable categories: product-on-white shots (ecommerce), real estate interiors, food photography, diagrams and screenshots, UI mockups, charts and infographics, stock-style photography. In these cases the descriptive layer is the entire job, and AI handles it cleanly. Output usually ships with one quick edit (often: cutting the “A photo of” preamble).
Categories that need more editing: photos of identifiable people, photos with cultural context, decorative or branded imagery, abstract art, anything where the image’s purpose on the page differs from what is literally visible. The model will accurately describe the pixels but miss whatever is making the image worth using.
Categories where AI alt text is the wrong tool: charts and graphs that need their data described (an AI can say “a bar chart with five bars,” but the alt text needs to convey the actual data — which means the data has to come from the page author, not the image), and decorative images that should have empty alt text (alt=””) so screen readers skip them. Running these through an AI produces verbose alt text that screen-reader users have to listen through, which is worse than no alt text at all.
The three edits most AI alt text needs
Auto-generated alt text typically needs three small edits before it is shippable. The pattern is consistent enough to memorise:
1. Cut the preamble. AI tools default to starting with “A photo of…” or “An image showing…” or “This picture depicts…” Screen readers already announce that the element is an image; saying so in the alt text is redundant. Delete the first three to five words.
2. Trim to the relevant detail. AI tends to describe everything visible. Most alt text only needs to mention what is functionally important for the page. A blog post header image of a sunset over a beach with a person in the foreground does not need the alt text to mention the beach umbrella, the towel, the colour of the water, the cloud pattern, and the time of day — usually one or two of these are enough.
3. Add the page-context layer if the image needs it. If the image is illustrative (the purpose is the visible content), no addition needed. If the image is contextual (the purpose is something the visible content represents), add a short clause that names the context. “Sunset over Cape Cod beach” becomes “Sunset over Cape Cod beach, the location of the company’s 2024 retreat” if the page is about the retreat.
Length, tone, and the 250-character convention
WCAG itself does not enforce a character limit on alt text, but several conventions exist that are worth following.
Most assistive technologies — JAWS, NVDA, VoiceOver, Talkback — read alt text in a single uninterrupted stream. Past about 125 characters, the stream becomes long enough to lose the listener; past about 250 characters, it becomes long enough that some screen readers truncate or the listener gives up before the end. Aim for 80 to 150 characters as the comfortable range, and treat 250 as a hard ceiling.
Tone should be neutral and descriptive. Avoid evaluative or marketing language — “a stunning view of the ocean” tells the listener nothing about what is visible, only that someone thought it looked good. “A view of the Pacific Ocean from a cliff at sunset” is shorter and more useful.
Avoid keyword stuffing for SEO. Search engines have downweighted keyword-stuffed alt attributes since at least 2015, and screen-reader users find them genuinely annoying. Write the alt text for the listener, not for the crawler — the crawler will reward you anyway.
When you should not use AI alt text at all
Three categories where AI alt text is actively the wrong choice:
Decorative images. Images that exist purely as visual texture — separators, background patterns, illustration flourishes — should have empty alt text (alt=””) so screen readers skip them. Running these through any AI tool will produce a description, which is worse than no description.
Charts and data visualisations. The alt text for a chart needs to convey the data, which the AI does not have access to. The right approach is a short descriptive alt text plus a longer text equivalent in the page body or a linked data table — see W3C’s guidance on complex images.
Functional images (icons, buttons). The alt text for a magnifying-glass icon is “Search,” not “A black magnifying glass icon.” Functional alt text describes what the image does, not what it looks like — and that information lives in the page’s code, not in the pixels. The AI cannot infer it.
How this tool fits into an accessibility audit
The most useful place for an AI alt-text tool is inside a structured remediation workflow, not as a one-off generator. A pattern that works on real audits:
Run the image library through a scanner (axe DevTools, WAVE, Lighthouse) to get the list of images missing alt text. Sort by template — header images, product images, content images, decorative images — and decide per category whether AI alt text is the right approach for that category. For the categories where it is the right approach, run those images through this tool, paste outputs into a spreadsheet column, and have a human reviewer pass each row applying the three edits above. For the categories where AI is not the right approach (decorative, charts, functional icons), handle those separately with the right pattern.
A 500-image library can usually be remediated in 6 to 10 hours with this workflow versus 40+ hours of writing each alt text from scratch. The reviewer’s job becomes editorial judgement rather than copy production, which is the right shape for the work.