Accessibility has a reputation for being expensive. In reality, the cost depends almost entirely on when you start.
The numbers from our projects
In four projects where accessibility was a requirement from the start, the measured additional effort was between 2.5% and 4% of the frontend budget. In another four, where it was added after six months of development, remediation effort ranged from 22% to 31%.
The reason is simple: at the end you are not adding attributes, you are rebuilding structure.
What "from the start" means
- Semantic markup: a button is a
<button>, not a<div>with an event listener. - Contrast checked during design, not after implementation.
- Full keyboard navigation, tested on every new component.
- Labels and error messages correctly associated with form fields.
- A coherent heading structure that describes the page.
None of these points adds meaningful time once it is part of the team's habits.
Automated testing is not enough
Automated tools detect around 30% of issues. The rest appear only in real use: illogical tab order, messages that are never announced, focus traps inside a modal.
That is why we test every primary flow with a screen reader, and on public sector projects we invite real users before launch.
The side benefit
An accessible site is, almost always, also a faster site and one better structured for search engines. That is no accident: both depend on correct semantic markup.