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Screen Resolution Checker

Instantly see your screen resolution, browser viewport size, device pixel ratio, aspect ratio, orientation, and color depth. Values update live as you resize the browser window or rotate your device. Useful for web developers testing responsive designs, photographers checking display specs, and anyone troubleshooting a visual issue.

Screen vs Viewport vs Physical Pixels

Screen resolution is your full physical display size in CSS pixels \u2014 what most people mean by "my screen is 1920\u00D71080." Viewport is the usable area inside the browser window where web pages render, which is always smaller than the screen because browser UI (tabs, address bar, scrollbars) takes space. Physical pixels are the actual pixels on your hardware. On Retina or HiDPI displays, each CSS pixel is backed by 2\u00D72 or 3\u00D73 physical pixels \u2014 that's what device pixel ratio (DPR) measures. A viewport of 1024\u00D7768 at DPR 2 has 2048\u00D71536 physical pixels.

Common Use Cases

Filing a bug report where the developer needs to know the reporter's display details, and asking the user to dig through System Information is the slowest possible path. Designers confirming what device pixel ratio their main monitor actually reports, since "Retina" covers a wide range of physical densities. QA teams documenting test devices in a matrix and needing the exact viewport, screen, and DPR triple to identify each entry.

Web developers debugging why a media-query breakpoint hits differently on two monitors that "look the same." Anyone curious about the difference between their logical and physical pixel counts after macOS's "more space" scaling option or Windows' display-scale percentages. Browser extension and PWA authors verifying that their app reads viewport dimensions correctly across orientations on a real device, not just in DevTools emulation.

How We Compare

Operating-system info panes show screen resolution but typically not the browser viewport (which is what web layout actually uses) or the device pixel ratio. WhatIsMyScreenResolution.net and similar sites do, but show ads and may save the data they collect. Browser DevTools have the same info under "Sensors" or "Rendering," but only if you know where to look.

This tool surfaces screen dimensions, viewport dimensions, device pixel ratio, color depth, and orientation in one panel that updates live as you resize the window. Everything runs client-side, so the values reflect your actual session without telemetry. For testing how a page behaves at different viewport widths before resizing the browser by hand, see responsive breakpoint previewer.

Worth noting: the values shown reflect your current browser session at this moment. If you change display scaling, switch monitors, or rotate a tablet, the readings update live. The tool is read-only; it inspects what the browser already exposes via the screen and window APIs rather than measuring anything new.

Frequently Asked Questions

What is the difference between screen and viewport?+
Screen resolution is your full physical display size (e.g. 1920×1080). Viewport is the area inside the browser window where web pages render — smaller than screen size because it excludes browser chrome like tabs and address bar.
What is device pixel ratio?+
DPR is the ratio of physical pixels to CSS pixels. On a 'Retina' display, DPR is 2 or 3, meaning each CSS pixel is actually 2×2 or 3×3 physical pixels. This makes text and images render sharper.
Why is my viewport smaller than my screen?+
The browser uses some screen space for its UI (tabs, address bar, scrollbars). The viewport is the inner content area where your webpage renders, so it's always smaller than full screen size.
Does this work on mobile?+
Yes. The tool shows your phone's screen resolution, browser viewport, orientation, and pixel ratio. Rotate your device to see the values update.
What information does the tool show?+
Physical resolution (your screen’s native pixels), CSS resolution (what websites see), device pixel ratio (Retina/HiDPI factor), colour gamut (sRGB / Display P3), refresh rate, and orientation.
Why does my screen show one resolution in macOS but another here?+
macOS displays the "logical" resolution by default — a 2560x1440 Retina screen reports as 1280x720 to apps with a 2x device pixel ratio. The tool shows both so you can correlate macOS’s display setting with what websites actually see.
Can I detect multiple monitors?+
Only the screen currently rendering the page is detectable from the browser. For multi-monitor info, use OS settings or the Window Management API (Chrome 100+, requires permission).
Why does the tool report a viewport smaller than my screen?+
The viewport is your browser window’s inner content area, not the full screen. Browser chrome (tabs, toolbar) and OS chrome (dock, menubar) reduce viewport from full screen. Resize the browser to see the viewport adjust live.

📖 Learn More

Related Guide Screen Resolution Checker Guide →

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