Screen Resolution Checker
Instantly see what resolution your screen is running at, how big your browser window is, and your device pixel ratio — with the difference between them explained.
Everything you enter is processed in your browser and isn't sent to our servers.
How to use screen resolution checker
- 1Open the page — your screen details appear immediately.
- 2Compare the screen resolution (whole display) with the viewport (the part of the browser showing the page).
- 3Resize the window, zoom or rotate your device and watch the values update.
- 4Press Copy details to paste the results into a support ticket or bug report.
About this tool
Browsers report sizes in CSS pixels, the unit web pages are laid out in. On a standard desktop monitor at 100% scaling, one CSS pixel is one physical pixel. High-density displays — Retina Macs, most phones, and laptops with display scaling — use several physical pixels per CSS pixel; the device pixel ratio (DPR) tells you how many. Multiplying the screen size by the DPR gives an estimate of the physical resolution.
Example: an iPhone with a 390 × 844 CSS-pixel screen and a DPR of 3 has a physical resolution of about 1170 × 2532 pixels. A laptop set to 150% scaling on a 1920 × 1080 panel reports a 1280 × 720 screen with a DPR of 1.5.
The physical figure is an estimate: browser zoom changes the device pixel ratio, and some operating systems round values. The viewport is often what matters for web design and testing, because it's the space your page actually gets. Everything is read from your browser — nothing is sent to a server.
Frequently asked questions
Your operating system is probably using display scaling (for example 125% or 150%), which makes text and icons larger. Websites then see the scaled size in CSS pixels. The estimated physical resolution multiplies it back by the device pixel ratio.
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