What is screen resolution?
Screen resolution is the physical pixel grid of your display, for example 1920×1080 (Full HD) or 3840×2160 (4K). Websites read it via screen.width × screen.height. It tells you the panel size — not how much of it the browser window uses.
What is viewport size?
The viewport is the area your page actually gets: the browser window minus toolbars, sidebars and devtools. A 1920-wide screen with a half-width window reports a ~960px viewport. Responsive sites adapt to the viewport, not the screen — which is why this page shows both and updates live as you resize.
What is device pixel ratio?
DPR is how many physical pixels back one CSS pixel. DPR 1 is a classic desktop display; DPR 2 (“Retina”) packs four physical pixels into each CSS pixel for sharper text. A 390px-wide phone with DPR 3 renders with 1170 physical pixels across. Designers multiply CSS sizes by DPR to ship crisp images.
Examples
iPhone 15: 393×852 CSS px at DPR 3. 1080p monitor: 1920×1080 at DPR 1. 4K monitor with 150% scaling: browser may report 2560×1440 CSS px at DPR 1.5. The numbers below are your real values right now.
How it works
Open this page and the embedded script queries only documented browser APIs. Nothing is installed, no account is needed, and results reflect your current browser profile — including extensions, private mode and OS display scaling.
Limitations
Support varies by browser. Privacy features (tracking prevention, user-agent reduction, fingerprint randomization) can generalize or withhold values. Treat results as a best-effort live snapshot rather than a certified hardware inventory.
Privacy
Detection runs in your browser. We do not store fingerprints or device reports. The only network call any tool makes is the optional public-IP lookup on /my-ip (via a third-party IP API, disclosed in the privacy policy).