Image generated with AI. Art direction: Grafica.
Responsive design testing often means two checks before launch: a phone and a laptop. A page can pass both and still break for everyone in between: a tablet held upright, a phone turned sideways, a browser window dragged narrow on a desktop.
On 12 October 2026 we read our own contact page at every width from 320 to 1440 pixels, eight pixels apart, loading it fresh each time: 141 readings. At 133 the page fit the screen. At eight it did not. From 528 to 568 pixels, and again at 864 and 872, the form ran past the right edge by up to 44 pixels, so the page was wider than the screen. At phone and laptop widths it fit.
We fixed it before this post went out.
Why the middle breaks
A layout is usually designed for a few target screens and told where to switch from one arrangement to the next. The switch points are where things break: a form changing from two columns to one, a picture losing its margin, a title drifting to the edge. The large picture at the top of our blog’s front page had no side margin between 601 and 1024 pixels until a review by eye caught it on 10 October.
How to check yours
- Open the page in Chrome, open the developer tools and turn on the device toolbar. Choose «Responsive», so you can type any width.
- Go from 320 to 1440 pixels in steps of 8 or less; a break can be narrow. Ours showed at 864 and 872 and was gone at 856 and 880. Reload the page at each width; some layouts only rearrange when the page loads.
- At each width, look for a sideways scroll bar, text touching an edge, and anything cut off on the right.
- Where something breaks, narrow it down to the width where it starts and the width where it stops. That range is what you hand to whoever fixes it.
- Start with the pages that earn money: the contact form, the checkout, the booking page.
The reload in step 2 matters. When we first measured by resizing one open page instead of loading it fresh, our mortgage calculator appeared to overflow by up to 741 pixels. Loaded fresh at 375, 768, 1072 and 1440 pixels, it fit. A check that cannot tell those two apart is measuring itself, not the page.
If you want your site read at every width before your next launch, talk to us.
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