Free tool
Mobile Breakpoint Tester
Preview a website, or your own HTML, CSS and JS, at phone, tablet and desktop widths. Free, with no login.
Width: 375px
Orientation: Portrait
Mode: URL
How to use it
How to Test Mobile Breakpoints
01
Add your page
Enter a website address, or paste your HTML, CSS and JS in the code tab and press Run.
02
Pick a width
Choose a preset, or drag the slider to find the exact point where your layout breaks.
03
Check the hints
In code mode, the tool flags horizontal overflow and very small text.
04
Share the result
Copy a link that reopens your setup, handy for bug reports and handovers.
Common mobile-first breakpoints: 320 to 430px for phones, 768px for tablets, 1024 to 1440px for desktops. This tool is a quick check and does not replace testing on real devices.
Found Layout Problems?
We design and build mobile-first websites in Hyderabad. Send us your site and we will tell you what we would fix.
Breakpoint Tester: FAQs
Why is my website preview blank?+
Many sites tell browsers not to show them inside another page (using X-Frame-Options or a Content Security Policy). That is a setting on their server and we cannot bypass it. Paste your code into the "Your code" tab instead, or use your browser's built-in device mode.
Is my code uploaded anywhere?+
No. The tool runs in your browser and does not send your code or URLs to our server. Note that a "Copy link" for code mode places your code inside the link itself, so only share it with people you trust.
Does this match real phones exactly?+
It matches the viewport width, which is what CSS breakpoints react to. It does not reproduce a real phone's browser, fonts or touch behaviour, so test on a real device before launch.
Why are the overflow and text checks missing in URL mode?+
Browsers do not let one site read the contents of another, for security. The checks work only on code you paste into the tool.