Screen Size Checker
See your screen resolution, viewport size, pixel ratio, and aspect ratio instantly — plus a checker for any resolution and the sizes worth designing for.
Check any resolution
Popular resolutions
Everything is read locally from your browser. Nothing about your device is sent or stored.
What you’re looking at
The big number is your screen’s resolution in CSS pixels — the units websites actually work with. Below it: your current viewport (this browser window, updating live as you resize), your device pixel ratio, the physical pixel count of your display, color depth, orientation, and whether the device reports touch input.
The distinction between those numbers trips up almost everyone. A modern phone might have a gorgeous 1440 × 3200 physical panel but report a 360 × 800 screen, because it renders at a 4× pixel ratio. Both numbers are true; they answer different questions. Our guide on device pixel ratio unpacks it.
The resolution checker
Type any width and height — or click a popular size — and get its aspect ratio, its common name (Full HD, 4K, QHD), and its megapixel count. Useful for checking what a client’s "design for 2560" actually means, or settling which of two monitors has more real estate.
For developers: the live viewport
Because the viewport numbers update as you resize, this page doubles as a quick breakpoint tester. Drag the window edge and watch exactly where your layout should flip. It’s not a replacement for real device testing, but it answers "what width am I actually at?" faster than opening dev tools.
Frequently asked questions
Why does my phone report a smaller resolution than its spec sheet?
Spec sheets quote physical pixels; browsers report CSS pixels, which are physical pixels divided by the device pixel ratio. A 1170 × 2532 iPhone panel with a 3× ratio reports 390 × 844. Websites are built against the CSS number.
What resolution should I design websites for?
Design responsively rather than for one size, but know the landmarks: 360-430 px wide covers most phones, 768-834 px tablets, 1366 and 1920 px the two most common laptop/desktop widths. Your own analytics beat any global chart.
Is any of this device information collected?
No. The page reads your screen properties locally in your browser and displays them to you. Nothing is transmitted or stored.