Glossary · Accessibility term
Operable
Operable is the second WCAG principle, and its one-line statement is that user interface components and navigation must be operable. In practice that means everything works by keyboard and nothing traps focus. People get enough time. Nothing flashes at a rate that can trigger a seizure. Navigation helps you find things and know where you are, and targets are big enough to hit. It is the largest principle in the standard, at 34 criteria across five guidelines, and it is where WCAG 2.2 did most of its work, adding five of its nine new criteria. If Perceivable is about taking information in, Operable is about being able to act on it, and the difference shows in the consequences. A missing alt attribute costs somebody information. A keyboard trap costs them the session.
In practice
Operable is where the users say the trouble is. Asked what they find most problematic, screen reader users put CAPTCHA first. Then interactive elements not behaving as expected, links and buttons that do not make sense, screens changing unexpectedly, and a lack of keyboard access. Most of that top five lands at least partly in Operable, and the order has barely moved in 14 years. The categories are described in users' words rather than in criteria, so treat the mapping as a rough one.
The numbering inside it is a trap and it bites hardest in the navigation guideline. New criteria in WCAG 2.2 were added to the end of their guideline rather than slotted in by level, so numeric order no longer tells you anything about the level. In that guideline 2.4.10 is AAA, 2.4.11 is AA, and 2.4.12 and 2.4.13 are AAA again. Read the level marker, never the number.
The most useful thing to know here is that keyboard access is not the whole of it. The guideline covering input beyond the keyboard exists precisely because some people drive the page with a pointing device they cannot be precise with. W3C says in terms that providing keyboard operability does not satisfy the pointer gesture rule. It works with a keyboard is the industry's shorthand for operable, and it is not enough.
Why it matters
Operable failures stop people rather than slowing them down, which is why 14 of its 34 criteria sit at Level A, more than any other principle. Only six more arrive at AA, the same number Understandable adds and well behind Perceivable's eleven. That is not a reason to expect a light Level AA audit here, because an AA audit tests the A criteria too, so Operable brings 20 rules to it and is still the largest thing on the list. What the shape does tell you is where the session-ending barriers sit. Mostly at the floor of the standard. Start at Level A.
What it covers
Anything the user has to do. Reaching a control, working it, having time to finish, getting back out, finding their way to the next thing, and not being harmed by the page while they do it. The seizure guideline is the only one in WCAG written as a prohibition rather than a requirement, which tells you what is at stake in that corner of it.
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Related terms
- POURPOUR is the field's shorthand for WCAG's four principles, which are Perceivable, Operable, Understandable and Robust.
- PerceivablePerceivable is the first of WCAG's four principles, and the standard states it as information and user interface components being presentable in ways people can perceive.
- UnderstandableUnderstandable is the third of WCAG's four principles, and it splits in two the way its own sentence does.
- RobustRobust is the fourth of WCAG's four principles, and it asks that content be built well enough for a wide variety of user agents, including assistive technology, to interpret it.
- Keyboard accessibilityKeyboard accessibility means every piece of functionality on the page can be operated through a keyboard interface.
Knowing the word is the easy part.
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