Your display, decoded
—
Visible page area in CSS pixels
—
Browser-reported screen size
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CSS screen × DPR; not guaranteed native resolution
- Device pixel ratio
- 1×
- Orientation
- Detecting…
- Viewport ratio
- —:1
- Full screen
- Off
Resize the window, rotate the device, or enter full screen to update the readings.
Free browser tool
Screen Resolution Test: Viewport, DPR and Pixels
Run a screen resolution test to see viewport size, CSS screen dimensions, device pixel ratio, orientation, fullscreen state, and estimated physical pixels.
Settings
Live measurement
Readings update automatically when the viewport, orientation, or full-screen state changes. Use Refresh after moving this window to another display.
Screen API: Available
How to understand your screen resolution test
Viewport
The part of the web page currently available to content, measured in CSS pixels. Browser controls and side panels can reduce it.
CSS screen size
The browser-reported screen dimensions in CSS pixels. Operating-system scaling can make this smaller than the panel’s hardware pixel grid.
Device pixel ratio (DPR)
The approximate ratio between device pixels and one CSS pixel for the current browser context.
Estimated physical pixels
CSS screen size multiplied by DPR. This is a useful estimate, not proof of the display’s native resolution.
The values update when the viewport, orientation, zoom context, or fullscreen state changes. If you use multiple monitors, move this window to the target display and refresh or resize it so the browser reports the current environment.
Why a browser may not know native monitor resolution
Browsers expose display information in a privacy-conscious, layout-oriented form. Operating system scaling, browser zoom, remote desktop, display mirroring, virtual machines, multiple displays, and privacy protections can all separate reported CSS dimensions from the physical panel grid. Multiplying screen width by DPR can therefore match the native resolution on one device and be wrong on another.
For the authoritative hardware mode, compare the result with Windows Display settings, macOS Displays settings, your graphics control panel, or the monitor specification. The browser result is most reliable for web layout and current viewport questions.
Technical reference: MDN: Window.devicePixelRatio and MDN: Screen.width.