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Browser Dimensions: View Viewport & Screen Size in Real Time

By Tooladex Team •
Browser DimensionsViewportResponsive DesignDeveloper Tools
Browser Dimensions: View Viewport & Screen Size in Real Time

Need to know your viewport size or verify breakpoints? The Browser Dimensions tool shows viewport, window, and screen dimensions in real time — and updates automatically as you resize. All values are read from your browser; no data is sent to any server.

Example: Open the tool and resize your browser window. Watch the viewport (inner) and window (outer) values update live. Copy the full JSON output to document dimensions for design specs or debugging.

What are Browser Dimensions?

Browser dimensions are the pixel measurements of your browser window and display. The viewport is the visible area for web content (excluding the address bar and scrollbars). The window includes the full browser chrome. The screen reflects your physical display. Understanding these differences helps with responsive design, media queries, and debugging layout issues.

The Tooladex Browser Dimensions tool reads these values directly from your browser’s JavaScript APIs. Everything runs locally; nothing is uploaded or stored.

Why Use a Browser Dimensions Tool?

Responsive design — Verify breakpoints and media query behavior at different viewport sizes. Resize the window and see exactly when layouts change.

CSS debugging — When 100vw or 100vh behave unexpectedly (e.g. scrollbar offset), check the actual viewport dimensions.

Documentation — Capture viewport sizes for design specs, testing guides, or bug reports. Copy the JSON output for easy sharing.

Device testing — Compare dimensions across different devices, zoom levels, and browser configurations. Device pixel ratio and color depth are included.

How the Browser Dimensions Tool Works

  1. Open the tool in your browser. Dimensions load automatically.
  2. Resize the window — values update in real time. No refresh needed.
  3. Review the cards — Viewport (inner), Window (outer), and Screen dimensions are shown with their corresponding JavaScript property names.
  4. Copy the JSON — Click “Copy JSON” to copy all dimensions in a structured format.

Viewport vs Window vs Screen

Viewport (inner) — window.innerWidth × window.innerHeight. The visible area for web content. Excludes address bar, toolbars, and scrollbars. This is what CSS media queries and 100vw / 100vh typically reference.

Window (outer) — window.outerWidth × window.outerHeight. The full browser window including chrome. Useful for testing window sizing or fullscreen behavior.

Screen — screen.width × screen.height. Your physical display resolution. screen.availWidth and screen.availHeight exclude the taskbar and other OS UI.

Frequently Asked Questions

Why does viewport differ from window?
The viewport excludes the browser’s UI (address bar, tabs, scrollbars). The window includes everything. On mobile, the address bar often hides on scroll, so the viewport can change.

What is device pixel ratio?
Device pixel ratio (DPR) is the ratio of physical pixels to CSS pixels. On Retina or high-DPI displays, DPR might be 2 or 3 — one CSS pixel maps to multiple physical pixels. This affects image sharpness and 1px border rendering.

Is my data sent anywhere?
No. All dimension values are read locally in your browser. Nothing is uploaded or stored.

Privacy

All processing runs in your browser. We don’t send or store any dimension data.

Try the Browser Dimensions Tool

Browser Dimensions

View your browser viewport, window, and screen dimensions in real time. Perfect for responsive design, breakpoint testing, and CSS media queries. Updates as you resize.

Try Tool Now

The Browser Dimensions tool is free, works in your browser, and requires no sign-up. Open it, resize your window, and get live viewport, window, and screen dimensions — perfect for responsive design and breakpoint testing.

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