Mobile-Friendly Checker
Enter a URL to check viewport configuration, responsive CSS signals, fixed-width elements and other mobile SEO signals.
Check a URL
What makes a page mobile-friendly?
Since Google moved to mobile-first indexing, the mobile version of your page is effectively the version that gets crawled and ranked. A correctly configured viewport, layout that reflows to the screen width, readable font sizes without zooming, and no dependence on unsupported plugins are the baseline requirements.
What this checker actually looks at
This tool fetches the live HTML of the URL you submit and scans for the same signals a crawler sees on first pass: whether a viewport meta tag exists and is configured correctly, whether the CSS shows signs of responsive design (media queries), whether inline styles set large fixed pixel widths that could force horizontal scrolling, whether legacy plugin content like Flash is present, and whether font sizes are set small enough to require zooming to read.
Common fixes
A missing viewport tag is the single most common issue and the easiest to fix — add <meta name="viewport" content="width=device-width, initial-scale=1"> to your page's <head>. Fixed-width elements usually come from an old desktop-first stylesheet; switching to relative units (%, rem, or CSS Grid/Flexbox) resolves most of these automatically.
Does this replace Google's own mobile testing tools?
No — this is a fast heuristic check on the raw HTML. For a full rendering-based assessment, also test the URL in Google Search Console's URL inspection tool.
My site is responsive — why did it still flag an issue?
Some CSS frameworks load styles from external files this tool can't scan, or use JavaScript to inject responsive behavior after page load. A warning here is a prompt to double-check manually, not a definitive failure.
New to this topic? Read Mobile-First Indexing Explained.