Screen Resolution Test: Verify Native Output, DPR & Scaling
What Windows reports as your resolution and what your panel actually lights up are not always the same number. This screen resolution test reads your display's physical pixels, device pixel ratio, and effective scaling directly from the browser, so you can confirm a monitor is genuinely outputting native 1080p, 1440p, or 4K — and understand what your system's 125% or 150% scaling is really doing.
Logical pixels vs. physical pixels
Every modern display stack has two coordinate systems. Physical (native) resolution is the grid of actual pixels on the panel — 1920×1080, 2560×1440, 3840×2160. Logical resolution is what applications see, after the OS applies scaling so that text and icons stay a usable size on dense screens.
The bridge between them is the device pixel ratio (DPR): at Windows 150% scaling on a 4K panel, applications see a 2560×1440 logical desktop backed by 3840×2160 physical pixels (DPR 1.5). On Retina Macs, DPR 2 is standard. Nothing is wrong — this is by design — but it means "my resolution is 2560×1440" in a settings dialog can describe three different physical situations.
This page reports both numbers plus the browser viewport, available work area, and aspect ratio, giving you the full picture in one glance — useful when a screenshot size does not match expectations or a game offers an odd resolution list.
Confirming you are actually running native
A 4K monitor fed a 1080p signal still "works" — it upscales, and softly. To confirm native output, compare the reported physical resolution against the panel spec. If they disagree, the GPU is scaling: check the OS display settings for the resolution dropdown (Windows hides non-native modes behind "list all modes"), and on laptops with hybrid graphics, ensure the browser runs on the dGPU when testing external displays.
Blurry text is the everyday symptom of non-integer scaling — 125% or 175% force the OS to resample UI assets. If text looks fuzzy at 125%, try 100% or 150% (integer multiples of 0.5 resample more cleanly), or enable per-application DPI awareness overrides for legacy apps.
Multi-monitor users should drag the test onto each display in turn: every panel reports its own numbers, and mixed-DPR setups (a 4K screen next to a 1440p) are where most scaling confusion and blurry-window bugs live. The viewport and taskbar deduction figures are also handy for verifying available work area after adding docks and toolbars.
What your resolution tier means in practice
1080p (Full HD) remains the compatibility baseline — everything targets it, GPU load is light, and at 24 inches the pixel density is adequate. 1440p (QHD) is the current sweet spot for 27-inch monitors: 109 PPI sits at the limit where individual pixels disappear at normal viewing distance without needing scaling.
4K (UHD) at 27–32 inches demands 150–200% scaling for comfortable text — which is exactly when the DPR readout above starts to matter, and when a refresh rate test becomes important too, because 4K at 144 Hz stresses cable bandwidth to its limits.
Ultrawide and superwide panels change the aspect-ratio readout rather than the density logic: a 3440×1440 ultrawide is a 1440p-class panel stretched horizontally. For evaluating panel quality itself — dead pixels, uniformity, color — move on to the screen test suite once your geometry is confirmed.
Frequently Asked Questions
What is my screen resolution?+
Run this page and read the physical resolution — the panel's actual pixel grid, e.g., 1920×1080, 2560×1440, or 3840×2160. It also shows the logical resolution your OS reports to apps after scaling, and the DPR connecting the two.
Why does my 4K monitor show 2560×1440 in some places?+
Because the OS applies scaling (150% at 4K is typical), and apps see a logical resolution rather than physical pixels. The physical readout on this page shows the true panel grid; if physical also shows 2560×1440, the GPU is upscaling and you are not running native.
What is device pixel ratio (DPR)?+
DPR is the multiplier between logical and physical pixels: DPR 2 means one application pixel maps to a 2×2 block of physical pixels. Windows 125% scaling is DPR 1.25, macOS Retina is DPR 2. It is why screenshots can be larger than your set resolution.
Is 125% scaling making my screen blurry?+
Possibly. Non-integer scaling factors resample UI assets, which softens text on some panels and apps. If text looks fuzzy at 125%, test 100% or 150% — or check whether the blur affects only specific legacy applications, which need their own DPI-override setting.
How do I check resolution on a second monitor?+
Drag the browser window fully onto the other display and reload — each panel reports its own physical resolution, DPR, and refresh capabilities. This is also the fastest way to spot which monitor in a mixed setup is causing blurry-window dragging between screens.