How it works
The page's layout is described in rules that depend on the screen width. Above a certain width, three columns sit side by side; below it, they stack into one. Images are told to never be wider than their container. Font sizes and spacing adjust. The same page, the same content and the same address serve every device, which is also why Google prefers it to separate 'm.' mobile sites.
Why it matters for a business
- Most visitors are on phones. For local service businesses, mobile is commonly 60 to 80 per cent of traffic. A site that is awkward on a phone loses most of its visitors.
- Google ranks the mobile version. Google's index is mobile-first: what your site shows on a phone is what gets ranked, even for desktop searches.
- Conversions. Tap-to-call buttons, short forms and readable text on a phone are where leads come from. See how to check whether your website is mobile friendly.
Responsive is the minimum, not the goal
A site can be technically responsive and still be bad on a phone: tiny tap targets, a hero image that pushes everything below the screen, pop-ups that cannot be closed, pages that take eight seconds to load on cellular data. Good mobile design means designing for the phone first and asking what a visitor with one thumb and thirty seconds needs. That is a design question as much as a technical one, and it is also what Google's Core Web Vitals try to measure.