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GEARCHECK LAB
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…

How to verify the browser-reported resolution

  1. Move this browser window onto the display you want to check.
  2. Press Refresh values, then record Screen Size, Device Pixel Ratio and Estimated Pixel Grid together.
  3. Maximize or resize the window and confirm that Viewport changes independently from Screen Size.
  4. Compare the estimated grid with the resolution selected in operating-system display settings; do not compare Screen Size alone.
  5. If you use multiple displays, move the window to each screen and refresh again. Record each result separately.
  6. Copy the report only after the values settle, and include the browser, OS scaling setting, zoom level and remote-session status in a support ticket.

What is my screen resolution?

The Screen Size value comes from window.screen. With operating-system scaling, it is often expressed in logical CSS pixels rather than the panel's raw pixel matrix. A high-density laptop or phone can therefore report smaller dimensions than its advertised resolution.

The Estimated Pixel Grid multiplies the reported dimensions by devicePixelRatio. That helps explain web rendering, but it is not direct monitor-firmware evidence.

Screen size, viewport and available area

Screen Size describes the whole display area exposed to the page. Available Screen may exclude operating-system UI such as a taskbar or dock. Viewport is the page's current drawing area inside the browser window.

Responsive sites normally react to viewport dimensions. Resize the window: viewport should change immediately while the reported screen usually remains stable.

Device pixel ratio and scaling examples

  • 1920 × 1080 at DPR 1: the estimated grid remains 1920 × 1080.
  • 1536 × 864 at DPR 1.25: the estimate becomes 1920 × 1080, a common pattern with 125% scaling.
  • 1440 × 900 at DPR 2: the estimate becomes 2880 × 1800, typical of a high-density logical desktop.

These are interpretations of browser signals, not proof of the panel matrix. Browser zoom, remote desktops and OS/browser combinations can change the mapping.

Interpret the result without overclaiming

LabelWhat you observedWhat it means
PASSScreen, DPR and estimated-grid values are stable and consistent with the selected OS display mode.The browser geometry is suitable for web-layout troubleshooting. This does not certify native resolution or panel quality.
WARNINGThe estimate differs from the advertised resolution, changes between browsers, or updates only after refresh.Check OS scaling, browser zoom, multi-monitor placement and remote-session behavior before treating the difference as a fault.
FAILValues are zero, remain stale after moving displays, or the browser report cannot reproduce the layout problem.The browser signal is insufficient for this diagnosis. Use OS display settings or hardware/EDID tools; the label does not mean the monitor failed.

Troubleshoot resolution and scaling mismatches

  • Advertised resolution looks smaller: check OS scaling and DPR together; logical CSS pixels are expected under scaling.
  • Soft images or canvas: compare viewport CSS size with Viewport Pixel Grid and confirm the asset supplies enough pixels.
  • Wrong monitor after moving the window: refresh values after the window is mostly on the target display; some environments update late.
  • Different results in a remote session: the remote desktop may expose a virtual display rather than the physical monitor.
  • Layout breaks only at one size: capture viewport, DPR, zoom, browser and orientation—not the screen size alone.
  • Orientation is stale: rotate the device, wait for the OS transition, then use Refresh values.

Browser, OS and panel limitations

  • A webpage normally cannot read a trustworthy monitor model, EDID record, native panel matrix, diagonal size or pixels per inch.
  • Different browsers may round, normalize or delay screen properties for privacy and compatibility.
  • Multi-monitor setups can use different scaling factors, and results may depend on which display owns most of the window.
  • Browser zoom can affect viewport measurements and, in some browser/OS combinations, the exposed DPR.
  • Color-gamut and dynamic-range media queries describe a browser capability class; they do not measure accuracy, coverage or brightness.
Use this readout to reproduce web-layout conditions. Use operating-system or hardware tools for native-resolution and panel-identification claims.

Choose the focused display test

Use the Dead Pixel Test for fixed visible points, the Refresh Rate Test for browser-observed frame cadence, the Ghosting Test for motion trails, and the Full Display Test for gradients and sharpness patterns.

The resolution checker reports geometry only. Keeping those workflows separate prevents a browser signal from being presented as a physical-panel diagnosis.

Screen resolution checker FAQ

Does browser screen size always equal native monitor resolution?

No. Browsers can report logical CSS dimensions affected by operating-system scaling, browser behavior, remote sessions and device pixel ratio. The estimated pixel grid is context, not proof of the panel matrix.

Why does 1920 × 1080 sometimes appear as 1536 × 864?

A common explanation is 125 percent operating-system scaling: the browser may expose 1536 by 864 CSS pixels with a device pixel ratio near 1.25. Multiplication estimates 1920 by 1080, but the result is not a native-resolution guarantee.

Can this page detect my monitor's physical size or PPI?

Not reliably. Standard browser APIs normally do not expose a trustworthy physical diagonal or panel dimensions, so this page does not calculate pixels per inch.

Why does the viewport change while screen size stays the same?

The viewport is the page area inside the browser window. It changes with window size, browser chrome, zoom and device rotation, while the reported screen dimensions usually remain stable.

How should I compare two monitors?

Move the browser to each monitor, refresh the values, and record screen size, DPR and viewport separately. Browsers and operating systems may delay or normalize screen updates, especially in remote sessions.

Does high dynamic range mean a specific HDR brightness?

No. It is only a browser media-query capability signal. It does not measure peak luminance, black level, color accuracy or HDR certification.