What is the difference between screen resolution and viewport size?

Screen resolution is the total number of pixels your display can show (e.g., 1920×1080). Viewport size is the area of the browser window available for web content, which is smaller because it excludes browser toolbars, address bars, and scrollbars.

What is device pixel ratio (DPR)?

DPR is the ratio of physical pixels to CSS pixels on your display. A Retina display with DPR 2 means each CSS pixel maps to 2×2 physical pixels. This affects how images and text are rendered — a 1440px-wide viewport on a 2x display actually has 2880 physical pixels.

Why does the checker show different values than my monitor's native resolution?

If your operating system uses display scaling (e.g., 125% or 150% on Windows), the browser reports the scaled resolution rather than the native resolution. The DPR value helps you understand the relationship between the reported and physical pixels.

Can I use this on my phone?

Yes. The checker works on any device with a browser. On mobile, the screen resolution typically matches the device's native resolution, and the DPR is often 2x or 3x for high-DPI screens.

Does the viewport update when I resize my browser?

Yes. The viewport dimensions update in real time as you resize your browser window. This is useful for testing responsive breakpoints — you can see exactly when your layout crosses a breakpoint threshold.

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Screen Resolution Checker

Your screen resolution is detected automatically using the browser's Screen API. For example, a 1920×1080 display with DPR 2 has a viewport of 1920×1080 CSS pixels but 3840×2160 physical pixels. Our free screen resolution checker shows resolution, viewport, DPR, and pixel density instantly.

100% FreeNo Signup RequiredBrowser-BasedPrivate & Secure

What is Screen Resolution Checker?

A screen resolution checker is an online tool that detects and displays your current screen resolution, viewport size, device pixel ratio, and pixel density using the browser's native APIs, providing a complete display characterization without any user interaction.

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These tools work great alongside Screen Resolution Checker:

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Knowing your exact screen resolution, viewport size, and device pixel ratio is essential for responsive web development and display troubleshooting. This free screen resolution checker detects everything automatically the moment the page loads, with real-time viewport updates as you resize — so you always have the exact numbers you need.

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