Screen and viewport details
Screen Resolution Test
See screen size, browser viewport, device pixel ratio, estimated physical pixels, orientation, and color depth.
Screen Resolution Test
What this tool measures
CSS pixels, device pixels, and the browser viewport are different measurements. Device pixel ratio connects the CSS viewport to an estimated backing-pixel size.
How to use it
- Read the screen and viewport values.
- Resize the browser to see viewport values update.
- Use full screen to reduce browser chrome when comparing dimensions.
Why people check screen resolution
- Find the reported resolution of a computer or phone
- Explain why webpage and screenshot dimensions differ
- Compare operating-system scaling, browser zoom, and DPR
Screen size, viewport, and DPR
Screen size is the display area reported by the browser, the viewport is the space available to the page, and DPR relates CSS pixels to device pixels.
Repeat the test
Use several runs under the same conditions before drawing a conclusion from a single value.
Compare like with like
Keep the browser, window size, device connection, and power mode consistent when comparing results.
CSS pixels are not physical pixels
At 150% system scaling or a different browser zoom level, the same panel can report different CSS dimensions.
Physical pixels are estimated
Screen CSS size multiplied by DPR is useful context, but privacy protection and multi-monitor setups can make it differ from native panel resolution.
Measurement limits
Browser zoom, display scaling, multiple monitors, and privacy protections can affect reported values.
Privacy
Measurements are calculated locally in your browser and are not uploaded by the tool.
When resolution data looks unexpected
Keep the page active
Background-tab throttling, browser extensions, and other busy applications can affect browser measurements.
Retest under controlled conditions
Reload the page, keep the same settings, and repeat the measurement before treating an outlier as a fault.
Check both scaling controls
Operating-system display scaling and browser page zoom both affect CSS dimensions and should be checked together.
Account for multiple monitors
After moving a window to another display, DPR and available size may update only after a resize or window event.
Screen resolution questions
Is this a hardware certification test?
No. It is a browser-side diagnostic intended for comparison and troubleshooting, not laboratory certification.
Where is the test data processed?
The measurement is calculated in this browser tab and the tool does not upload the raw test input.
Does a higher DPR always mean a sharper display?
No. DPR is only the ratio between CSS and device pixels; physical size and native resolution also determine pixel density.
Why is the viewport smaller than the screen?
Browser toolbars, sidebars, window borders, and non-fullscreen mode all reduce the area available to the webpage.