# WCAG 2.2 – 3.3.4 Error Prevention (Legal, Financial, Data)

- Level: AA
- Principle: 3 Understandable
- Guideline: 3.3 Input Assistance
- Introduced in: WCAG 2.0

## What the rule requires

For important actions such as purchases, contracts, test answers or deleting data, people can review, correct or undo their input.

## How to get it right

Show a summary page with “Change” links and a clear “Place order and pay” button before the purchase.

## Who benefits

- People with cognitive disabilities
- People with motor disabilities
- Everyone

## Sources

- [This rule on wcag.dehl.net](https://wcag.dehl.net/en/wcag/3-3-4/)
- [Official W3C explanation](https://www.w3.org/WAI/WCAG22/Understanding/error-prevention-legal-financial-data)
- [Techniques (WCAG Quick Reference)](https://www.w3.org/WAI/WCAG22/quickref/#error-prevention-legal-financial-data)

_Plain-language explanation. Only the original W3C text is normative._