Comparisons
Comparisons
Many accessibility terms sound alike but solve different problems. A photo caption doesn't replace alt text, and captions don't always replace a transcript. The tables below sum up the general traits to help you figure out what your page actually needs and where to start.
The best option isn't the most complete one. It's the one you can actually keep up on every new page.
About this section: the tables describe the typical picture in general terms and don't replace the guidelines themselves. For the exact wording of each requirement, read the primary source: the WCAG guidelines.
Levels A, AA and AAA
| Feature | A | AA | AAA |
|---|---|---|---|
| What it roughly means | Basic requirements; without them, some people can't use the site at all | Requirements that remove the most common barriers | The strictest requirements, for special cases |
| Example in spirit | Images have descriptions; everything works with a keyboard | Normal text contrast of at least 4.5:1, large text at least 3:1 | Even higher contrast; sign language for video |
| How it relates to the others | The lowest level | Includes all level A requirements | Includes all level A and AA requirements |
| What people usually aim for | The required minimum | A reasonable goal for most websites | Selected pages and materials, not the entire site |
Alt text vs. caption vs. transcript
| Feature | Alt text | Caption | Transcript |
|---|---|---|---|
| Who sees it | Not shown on screen; read by a screen reader, or displayed by the browser if the image fails to load | Visible to everyone below the image | Visible to everyone next to the content or via a link |
| Length | One or two short phrases | Anywhere from a few words to a paragraph | The full text of everything said and shown |
| Purpose | Replace the image for people who can't see it | Add to the image: who, where, when, source | Replace audio or video entirely with text |
| Typical mistake | A file name or the word “image” instead of the meaning | Repeating the alt text word for word | A summary instead of the full text |
Subtitles vs. transcript vs. sign language
| Feature | Subtitles and captions | Transcript | Sign language |
|---|---|---|---|
| What it is | Text of the speech and key sounds shown over the video, in sync with it | A separate text version of the whole video or audio recording | Interpretation into sign language by an interpreter shown on screen |
| Who it helps | People who can't hear and anyone watching with the sound off | People who can't hear or see, and those who prefer to read | People whose first language is a sign language |
| Why it's useful | No need to look away from the video | Read at your own pace and search the text | Conveys tone and meaning in a familiar language |
| Where a small site should start | Videos that cover the most important topics | Podcasts and audio-only recordings | Selected key materials |
Related reading
- Guides
Step-by-step guides to making text readable, organizing a page with clear headings and building a contact form that works for everyone. Plus the article catalogue.
- Tools
How to check a site yourself: browser zoom, the keyboard, high contrast mode, the built-in screen reader, color contrast checks and a markup validator.
- Fixes
What to do when focus is invisible, text breaks on zoom, a button has no label, form errors make no sense or a video has no captions.
- Glossary
Key terms explained: accessibility, WCAG, GOST R 52872-2019, contrast, alt text, focus, screen readers, captions and plain language.
- Questions
Answers to common questions about this reference, text and images, forms and video, and how to check your own site's accessibility without an expert.
Sources
- W3C: WCAG 2.2 Recommendation
- GOST R 52872-2019 (Russian national standard)
- Wpget editorial materials
This information is stated in general terms as of the preparation date. Guidelines, browsers and reader habits change over time, so when in doubt, check the primary sources: the text of the WCAG guidelines and, for Russia, the current GOST R 52872-2019 standard.