What's My Browser Size

Your data never leaves your browser

Detect your current browser window size, screen resolution, and device pixel ratio.

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About What's My Browser Size

Click Generate to see your browser's viewport dimensions (innerWidth × innerHeight), full screen resolution (screen.width × screen.height), available screen size, and device pixel ratio. Useful for responsive design testing and bug reports.

How to use

  1. Click the Generate button.
  2. Your viewport size, screen resolution, and pixel ratio appear in the output panel.
  3. Resize your window and click Generate again to see updated values.

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Frequently Asked Questions

FAQs about What's My Browser Size

What is the difference between viewport and screen size?

Viewport (innerWidth × innerHeight) is the size of the visible area inside the browser window. Screen resolution (screen.width × screen.height) is the full physical display resolution.

What is device pixel ratio?

Device pixel ratio (DPR) is the ratio of physical pixels to CSS pixels. Retina and high-DPI displays have a DPR of 2 or 3, meaning one CSS pixel maps to 2–3 physical pixels.

Why would I need this?

This is useful for responsive design debugging, screenshot tools that need to know viewport dimensions, and filing UI bug reports that include display context.

Does this update if I resize my browser?

The values are captured at the moment you click Generate. Click Generate again after resizing to get updated measurements.

Is my data safe?

Everything runs in your browser. No data is sent to any server.