Open the page at the browser size you want to inspect. The report updates on resize and distinguishes CSS pixels from the device-pixel estimate derived from devicePixelRatio.
Summarize viewport, DPR, device pixels, aspect ratio and megapixel workload.
| Metric | Value | Meaning |
|---|
These pages can report Web API data such as events, stream settings, frame timing and audio samples. They do not certify hardware condition or bypass browser and operating-system limits.
The page no longer encourages treating screen.width × DPR as guaranteed panel-native resolution. OS scaling, browser zoom, mirroring and remote sessions can change the relationship.
Use the interactive product above first. These notes add interpretation, verification and limits below the results and product controls.
window and screen dimensions exposed to a web page are often expressed in CSS pixels. Multiplying by devicePixelRatio can estimate a device-pixel backing size, but that is not a promise of the panel’s native hardware resolution.
Toolbars, side panels, zoom and responsive layout reduce the page viewport even when the operating system reports a larger screen area. Record both values when diagnosing a layout issue.
Display scaling can produce values such as 1.25 or 1.5. Do not round devicePixelRatio before multiplying dimensions if you are using it to estimate the browser rendering budget.
Desktop browser zoom can alter CSS-pixel measurements and DPR behavior. Re-check at 100% zoom when comparing devices, then deliberately test the zoom levels your users actually use for accessibility.
Two screens can have the same pixel dimensions but very different physical dimensions and pixel densities. Use physical size or PPI information separately when the question is about real-world size rather than layout capacity.
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