Responsive Design Tester
Preview a web page at different screen sizes to check it works on phones, tablets and desktops.
Seeing your page at every size
A page that looks perfect on your laptop can be a mess on a phone — text overflowing, buttons too small, a layout that does not reflow. This shows a page at a range of common device widths side by side, so you can check that your responsive design actually holds up across phones, tablets and desktops without dragging your browser window around and guessing.
Load the page and see it rendered at several screen sizes at once.
Mobile is where most visitors are
For most sites, more than half the traffic is on phones, and Google indexes the mobile version of your page first, so the small-screen view is not an afterthought — it is the main event. The usual trouble spots are wide images and tables that do not shrink, text that stays tiny, and tap targets too close together. Checking the narrow widths first, rather than last, catches the problems that affect the majority of your visitors.
Responsive Design Tester FAQ
Why test at different screen sizes?
Because a layout that works on desktop can break on a phone, and most visitors — and Google's indexing — are on mobile first.
What usually breaks on mobile?
Wide images and tables that do not shrink, text that stays too small, and tap targets placed too close together.
Is anything uploaded?
No. The preview runs in your browser.