Level AA · WCAG 2.0
3.3.3 Error Suggestion
When a form knows how to correct an error, the message says how — the format expected, the range allowed, the nearest valid choice.
Manual only No automated check says anything useful.
How it fails in practice
“Invalid input” under a date field that knows exactly which format it wants. “Password does not meet the requirements” without listing them. The form has the answer and keeps it to itself.
How to fix it
Write every validation message as the fix: “Enter the date as day, month and year, for example 21/03/1990.” The exception is where saying more would compromise security — which is why a login may say only that the details did not match.
At a glance
- Level
- Level AA — the level EN 301 549 requires, and therefore the level the BFSG and the EAA are measured against.
- Principle
- Understandable
- Guideline
- 3.3 Input Assistance
- Added in
- WCAG 2.0
- EN 301 549
- 9.3.3.3
- Automated check
- Manual only
How to test it by hand
- Submit each validated field with a value in the wrong format: a date, an email address, a postcode, a phone number.
- Submit a value that is out of range or not on the list — a quantity of zero, a date in the past for a booking.
- Read each message on its own and ask whether you could correct the field from it without guessing.
- Check the message is tied to its field (
aria-describedby), so a screen reader reads the suggestion when focus returns to it.
In code
<label for="dob">Date of birth</label>
<input id="dob" name="dob" aria-invalid="true" aria-describedby="dob-error">
<p id="dob-error">Invalid input.</p><label for="dob">Date of birth</label>
<input id="dob" name="dob" aria-invalid="true" aria-describedby="dob-error">
<p id="dob-error">Enter the date as day, month and year, for example 21/03/1990.</p>Manual only
How far an automated check gets
Nothing automatic decides this. A scanner that reports it as passing is reporting that it did not look. It stays untested until a person tests it and records what they did — which is exactly how we treat it: as untested, not as passed.
Our scan never types wrong answers into your forms, so it never sees the messages this criterion is about. A person checks it, making the mistakes on purpose.
Related criteria
Other criteria under the same guideline.
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