Free Responsive Design Checker

Why responsive design affects your rankings

Google uses mobile-first indexing — the mobile version of your page is the one it crawls, renders and ranks. If content overflows the screen, images spill past the edge, or tap targets sit too close together on a phone, that is the experience Google records, even when your desktop layout looks perfect. Layout that shifts as it loads also hurts your Core Web Vitals, and a page users have to pinch and pan simply converts worse. Checking real device widths before you ship catches these problems while they are still cheap to fix.

How to read your responsive results

The tool renders a full-page screenshot at each device width so you can scroll the real page as a phone, tablet or desktop would see it — switch devices in the gallery to spot exactly where a layout breaks. Alongside the preview you get a 0–100 responsive score, whether a viewport meta tag is present, how many CSS media queries the page uses, and a prioritised list of findings. Work the findings top-down: a red criticalitem (like horizontal scroll or a missing viewport tag) outweighs any number of blue notices.

Fixing the most common responsive problems

• Overflowing images — add max-width: 100%; height: auto so pictures scale to the column instead of forcing the page wider.
• Fixed-pixel widths — swap hard width: 960px containers for relative units or max-width with a fluid fallback.
• Wide tables and code blocks — wrap them in a scroll container so one element can’t stretch the whole layout.
• Too few media queries — a page with none rarely adapts; add breakpoints where the design starts to feel cramped, not at arbitrary device sizes.

Re-run the check after each change and watch the score climb — a clean pass across all three widths is a strong signal your mobile experience is ready to rank.