What Is My Screen Resolution?
Your screen resolution, browser viewport, and pixel density — updates live as you resize.
How to Use This
- The values above are read automatically — nothing to click.
- Resize your browser window to see the viewport size update live.
Frequently Asked Questions
What's the difference between screen resolution and viewport size?
Screen resolution is your entire monitor or display's total pixel dimensions. Viewport size is just the visible browser window area actually available for a webpage, which is smaller once you subtract the browser's toolbars, tabs, and any other chrome around the page.
What does the device pixel ratio mean?
It's the ratio between physical device pixels and CSS pixels. A ratio of 2, common on high-density "Retina"-style displays, means the screen packs 2×2 real pixels into the space of what a webpage treats as a single CSS pixel, producing sharper text and images.
Why do these numbers update if I resize my browser window?
The viewport size specifically reflects your current browser window, so it updates live as you resize the window — this is useful for testing how a responsive website design behaves at different widths.
Is any of this sent to a server?
No — every value shown is read directly from your own browser using JavaScript, and none of it is ever sent anywhere.