Accessibility
Accessibility statement
Everyone should be able to use these guides and tools. Here is what we have done and how to tell us when something gets in your way.
Our goal
We aim to follow the Web Content Accessibility Guidelines (WCAG) 2.2 at level AA. We have not had the site independently audited, so we do not claim full conformance, but we test as we build and fix problems when we find them.
What is built in
- Every page can be used with a keyboard, with a visible focus outline and a skip link to the main content.
- Headings follow a logical order, and landmarks mark the header, navigation, main content and footer.
- Calculators announce their results to screen readers as values change.
- Text and buttons meet AA color contrast against their backgrounds.
- Animations are switched off when your device asks for reduced motion.
- Text can be enlarged to 200 percent without losing content.
- Photos have text descriptions, and decorative images are hidden from screen readers.
Known limits
The translate menu relies on Google's translation service, which we do not control; translated pages may not read as smoothly with assistive technology. The range sliders in the tools also accept typed values in the elevation panel for anyone who finds sliders hard to use.
Report a barrier
If something on this site is hard to use, please tell us through the contact form, choosing "Something on this site" as the topic. Mention the page and what happened, and the assistive technology you use if you are comfortable sharing it.