Display Lab // Browser-Reported Geometry

SCREEN RESOLUTION CHECKER

See what your browser currently reports for the full screen, available screen area, page viewport, device pixel ratio, estimated pixel grid, color depth, orientation and selected display-capability signals. Values update live when the browser window changes size or the device rotates.

LOCAL READOUTThe page reads standard browser display properties and renders them here. No display permission is requested.

Live display report

Screen, viewport and pixel-density signals

LIVE

SCREEN SIZE · CSS PIXELS—What window.screen reports after OS/browser scaling.

ESTIMATED PIXEL GRID—Screen CSS dimensions multiplied by devicePixelRatio; not guaranteed to equal the panel's native pixel grid.

VIEWPORT—Current page drawing area.

AVAILABLE SCREEN—Browser-reported area excluding reserved OS UI where exposed.

DEVICE PIXEL RATIO—Physical-device-pixel to CSS-pixel scaling factor exposed to the page.

ASPECT RATIO—Reduced ratio from browser-reported screen dimensions.

COLOR / PIXEL DEPTH—Browser-exposed colorDepth and pixelDepth values.

ORIENTATION—Screen orientation API value when available.

TOUCH POINTS—navigator.maxTouchPoints.

COLOR GAMUT—Highest CSS media-query gamut reported by the browser.

DYNAMIC RANGE—Browser media-query signal, not a calibrated HDR brightness measurement.

VIEWPORT PIXEL GRID—Viewport CSS dimensions multiplied by DPR.

Reading display values…

What is my screen resolution?

The first value on this page is the screen size your browser reports through window.screen. On a display using operating-system scaling, that value is often expressed in CSS pixels rather than the panel's raw physical pixel grid. That is why a high-density laptop or phone may report smaller screen dimensions than the marketing resolution you remember.

GearCheck Lab therefore shows the browser-reported screen size and, separately, an estimated pixel grid created by multiplying those dimensions by devicePixelRatio.

Why the estimated pixel grid is not called native resolution

A webpage normally cannot ask the monitor firmware for its exact native panel matrix. Operating-system scaling, browser behavior, remote sessions, zoom-like environments and multi-display arrangements can all affect what standard web APIs expose.

The DPR multiplication is a useful estimate for web rendering and support work. It is not a guarantee that the monitor physically contains exactly that many pixels.

Screen size vs viewport size

Screen size describes the whole display area the browser reports. The viewport is the content area available to this page inside the current browser window. Resize the window and the viewport changes immediately while the underlying screen usually stays the same.

Responsive websites use viewport dimensions for layout decisions, so the viewport value is often more useful than full-screen dimensions when reproducing a web-design or support issue.

What device pixel ratio means

Device pixel ratio, or DPR, describes how browser CSS pixels map to device pixels. A DPR above 1 is common on high-density screens and when display scaling is enabled. It affects how many image pixels may be useful for sharp rendering, but DPR by itself does not tell you the physical screen size or pixels per inch.

GearCheck Lab deliberately does not invent a PPI or diagonal size from DPR because a browser does not normally know the monitor's true physical dimensions.

Color gamut and dynamic-range signals

The page checks CSS media queries such as color-gamut and dynamic-range. These tell you what capability class the browser reports to web content. They are useful compatibility signals, but they do not measure color accuracy, brightness, black level, coverage percentage or HDR peak luminance.

For calibrated display claims you need appropriate measurement hardware and a controlled workflow.

Useful troubleshooting examples

Copy the report into a support ticket when a layout only breaks at one viewport size.
Compare DPR and viewport when images look soft on one high-density device but not another.
Check orientation and viewport changes when debugging tablet or phone rotation behavior.
Use the estimated grid only as context before running the dead-pixel or refresh-rate diagnostics.
If the value differs from your monitor's advertised resolution, check operating-system scaling and display settings before assuming the browser or monitor is wrong.