What Is My Screen Resolution

What is the What Is My Screen Resolution tool?

What is my screen resolution? This tool answers that question the moment the page loads. It reads your display directly from the browser and shows your full screen resolution (the width and height of your monitor in pixels), your live browser viewport size, your device pixel ratio, the resulting physical pixel count, your color depth and the current orientation. No typing, no guessing, no account — your numbers appear instantly. The one thing it does that most rivals don't: it makes clear that screen resolution, browser viewport, and physical pixels are three different things, so you walk away actually understanding your display instead of staring at a single ambiguous number.

How to use it

1. Open the page. Your screen resolution and viewport size are detected and displayed automatically — there is nothing to click.
2. Read the Screen resolution row for your full display size (for example 1920 x 1080).
3. Read the Viewport row for the visible area inside your browser window right now.
4. Resize or rotate your browser window and watch the viewport numbers update live — handy for testing responsive breakpoints.
5. Check the Device pixel ratio and Physical pixels rows if you need the true hardware pixel count for high-DPI screens.

That's it. One glance, you have the answer, you're done — exactly how a utility should work.

The method behind it: screen vs. viewport vs. physical pixels

Screen resolution, browser viewport, and physical pixels are three different things, and these four numbers trip up almost everyone — so here is the plain-English version.

• Screen resolution comes from window.screen.width and window.screen.height. It describes your whole physical display — the spec you'd see advertised, like 1920 x 1080 or 2560 x 1440.
• CSS / logical pixels are the units your browser lays pages out in. Because of operating-system display scaling, these can be fewer than your panel's real pixels.
• Browser viewport comes from window.innerWidth and window.innerHeight. It's only the visible content area inside the browser window — it excludes tabs, the address bar and the OS taskbar, and it shrinks whenever the window isn't maximized. This is what web designers actually build against.
• Device pixel ratio (DPR) comes from window.devicePixelRatio. It's how many physical pixels render one CSS pixel. A normal screen is 1; a Retina or HiDPI screen is often 2 or 3. Physical pixels = logical size × DPR. A 1280-wide viewport at DPR 2 is really 2560 physical pixels wide, which is why Retina screens look so sharp and why images for them must be exported larger.

Every value is read live from your own browser — the exact same APIs that real websites use to serve responsive layouts — so the result is the ground truth, not an estimate.

Examples

• Full-HD laptop, no scaling: Screen resolution 1920 x 1080, DPR 1, physical pixels 1920 x 1080. The screen, logical and physical numbers all match because there's no scaling and no HiDPI panel.
• MacBook with a Retina display: Logical screen 1512 x 982, DPR 2, physical pixels 3024 x 1964. The panel has far more pixels than the logical number suggests — the DPR is the multiplier that reveals it.
• Phone in portrait, then landscape: Viewport 390 x 844 rotates to 844 x 390 the instant you turn the device, and the orientation label flips with it.

Common use cases

• Responsive web design and CSS debugging — confirm the viewport width you're testing against and watch breakpoints trigger as you resize.
• Filing a bug report or support ticket — many forms ask "what is your screen resolution?"; copy the exact figure in one second.
• Buying or returning a monitor or laptop — verify the panel really reports the resolution you paid for, and use DPR to understand any scaling difference.
• Picking a wallpaper or game resolution — match physical pixels so images fill the screen without blur or letterboxing.
• Designers exporting assets — read the DPR to know whether to export 1x, 2x or 3x artwork for crisp results.

Why use this one

Most "screen resolution" pages print a single number and call it done — and often that number is the viewport, mislabeled as the resolution. This tool separates screen resolution, browser viewport and physical pixels so you see all three and understand which is which, updates the viewport live as you resize or rotate, and includes a built-in device pixel ratio explainer so the scary DPR number finally makes sense. It runs entirely in your browser — nothing is uploaded, there's no sign-up, and it loads instantly. It sits alongside a couple of related network tools: What Is My IP for your public address and What Is My User Agent for the exact browser string your device reports.

Frequently asked questions