Presets
Phones
Tablets
Desktop
Size70%4 devices · full-width auto-fit
Enter a URL and press Preview to render it across 4 devices at once — they fill the full width of your screen.
How to use
01
Load your URL
Type the address, with or without https, and press Preview. The default Multi-device canvas renders the page across the Essentials preset: iPhone 15, Pixel 8, iPad Air, and a MacBook.
02
Pick devices and presets
Toggle any of the 12 devices, from the 360px Galaxy S23 up to a 1920px Desktop HD, or apply a preset like All phones. The Size slider scales every frame to fit your screen.
03
Switch modes if frames stay blank
Direct mode embeds the live site as-is. If a page refuses to render, click Device UA so the tool re-fetches it with that device's real user-agent, then press Reload all.
Why Mobile Responsive Checker
- Test one URL across many real devices at once — phones, tablets and laptop fill the full width of your screen with no horizontal scrolling.
- True-to-life device frames (iOS Dynamic Island, Android punch-hole, iPad, laptop) at each device's exact viewport and pixel ratio.
- Compatibility mode re-fetches with the real device user-agent so UA-sniffing and embed-blocking sites still load.
Common questions
How is this mobile responsive checker different from resizing my browser?
Three ways. It uses each device's true CSS viewport and pixel ratio instead of arbitrary window widths, it can present a dozen sizes simultaneously so regressions jump out, and its Device UA mode fetches the page with a real phone user-agent. A resized desktop window can't do any of that, and adaptive sites will actively mislead it.
Which device widths does the responsive checker cover?
Phones run 360px (Galaxy S23), 375px (iPhone SE), 393px (iPhone 15), 412px (Pixel 8), and 430px (iPhone 15 Pro Max). Tablets span 768px to 1024px across four iPads, and desktops go from a 1366px laptop through a 1512px MacBook to 1920px Desktop HD. That range brackets nearly every breakpoint a stylesheet defines.
Can I run a mobile friendly test on a site that blocks iframes?
Usually, yes. Sites that send X-Frame-Options or a frame-ancestors policy will show blank in Direct mode, but Device UA mode re-fetches the page server side and renders that copy instead. The caveat is that heavily JavaScript-driven pages may render differently in that mode than on a physical device.
Why do some frames stay blank in Direct mode?
The site is refusing to be embedded, which is a security setting, not a bug in your layout. Banking sites, Google properties, and anything with strict CSP headers do this. Switch to Device UA mode and hit Reload all; the frames re-fetch through the server and normally fill in.
Does the responsive design tester show rotated, wide orientation?
Yes. In Single device view, every phone and tablet has a rotate button that swaps the viewport dimensions, so a 393x852 iPhone becomes 852x393. Wide orientation catches a distinct class of bugs, like fixed headers eating half the visible height, that portrait testing never reveals.
Is checking a site on emulated device sizes as accurate as real hardware?
For layout and breakpoints, very close, since CSS responds to viewport width and pixel ratio and both are reproduced faithfully. What it can't reproduce is touch behavior, scroll physics, real rendering engines, or device performance. Use it to find layout breaks fast, then confirm critical flows on one physical phone.
What does the @2x or @3x label under each device frame mean?
That's the device pixel ratio: how many physical pixels the screen packs into each CSS pixel. An iPhone 15 at @3x renders your 393px-wide layout with three times the pixel density, which matters for image sharpness and srcset choices. The label helps you verify the tool is simulating the density your CSS targets.