FreeFree tool · no account needed
Free responsive design checker
Check your website on different screen sizes: an iPhone, an iPad and a laptop side by side, in a real browser. Not just pictures: every layout break is found, shown and explained.
Phone, tablet and laptopAbout a minuteNo sign-up
What it checks
What breaks between phone and desktop
Sideways scrolling
Content wider than the screen at any of the three sizes, and what causes it.
Overlaps
Text, buttons and pictures that run into each other as the layout narrows.
Cut-off text
Headings and labels clipped by a box that stopped growing.
Grids and gaps
Cards that leave holes in a grid, and big empty gaps between sections.
Menus and tap targets
Menus that spill off the screen, and buttons too small to tap on a phone.
Squeezed pictures
Logos squashed to a few pixels and photos stretched out of shape.
Three screens, about a minute
- 1
Paste your page
A live site, a staging link or a client preview: any public address.
- 2
We open it three times
Real Chrome at iPhone 17 (402px), iPad (820px) and laptop (1280px) sizes, scrolled and measured.
- 3
See where it breaks
The three screens side by side, and each problem with the sizes it happens at and the fix.
Guide
How to test a responsive website
- 01
Test the sizes people use, not just your own
Most visits come from phones between 360 and 430px wide, then laptops at 1280–1536px and Full HD monitors. Tablets sit in between, and that is where many layouts break: too wide for the phone layout, too narrow for the desktop one. - 02
Look between the breakpoints
A layout can look right at 390 and 768px and still break at 600px, where no breakpoint was designed. A free account's breakpoint sweep (Lens and Prism) resizes the page from 320 to 1920px in 10px steps and finds every width that scrolls sideways. - 03
Screenshots alone miss things
A picture doesn't say that a button is 20px wide or that text is clipped by one letter. This checker measures the page in the browser, so it reports what a tester would notice, with the element and a fix. - 04
Common fixes
Let flex rows wrap (flex-wrap: wrap), give imagesmax-width: 100%, replace fixed widths withmax-width, and let long words break (overflow-wrap: anywhere). The fix guides have the CSS for each problem.
Check your own page now
Free, in a real browser, about a minute. No account needed.
Questions
What is a responsive design checker?
A responsive checker tool opens your web page at phone, tablet and desktop screen sizes so you can see whether the layout adapts. Most only show the screens; this one also measures the page at each size and lists what broke, with the fix.
Which screen sizes does it check?
An iPhone 17 (402×874), an iPad (820×1180) and a laptop (1280×800), in Chrome. A free account checks 5 sizes, and paid plans add iPad landscape, Full HD, custom sizes and 30 more devices in Chrome, Safari and Firefox.
Is it better than other responsive testing tools?
Responsive viewers and screen size testers (browser extensions, device-frame sites, DevTools) show you the page and leave the bug-hunting to you. This responsive testing online tool does the looking: it finds sideways scrolling, overlaps, cut-off text and small tap targets, and names the element.
How is this different from a screenshot tool?
Screenshot tools show you the page; you still have to spot the bugs. This checker measures the page at each size and lists what is broken, where, at which sizes and how to fix it.
Can it check my whole site?
The free tool checks one page. A Lens or Prism account checks up to 15 or 250 pages in one go, and can monitor them every week.
Do I need an account?
No. You can run a few free checks without one. Your result has a private link that we never list or index.
Free, no account needed
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Three screens is a start. Check five, or the whole site.
Free account, 5 checks a day on 5 screen sizes, no card. Every problem marked on a screenshot, with the fix.