Screen resolution tester: check any display in seconds
A free tool to check the actual resolution, aspect ratio, and pixel density of any monitor, TV, or projector. No install needed.
You've just mounted a new TV in the conference room. Is it actually displaying at 1080p? Is the browser scaling it? What's the real aspect ratio? Instead of digging through display settings, just open a URL.
What it shows you
The Screen Resolution Tester displays four things the moment you open it:
- Viewport size — the actual CSS pixel dimensions the browser is using
- Screen resolution — the physical screen resolution reported by the device
- Aspect ratio — computed automatically (16:9, 4:3, 21:9, etc.)
- Pixel density (DPR) — whether the display is scaled (1x = no scaling, 2x = Retina/HiDPI)
When you need it
Setting up digital signage — Before you design content for a screen, you need to know what resolution it's actually rendering at. A "4K TV" might be running at 1080p if the source device is limiting it.
Troubleshooting display issues — Content looks blurry? Probably a scaling issue. This tool shows you the DPR so you can tell immediately.
AV setup — Projectors often negotiate a different resolution than what you expect. Open the tester on the projector and see what you're actually working with.
How to use it
Open the tool, click "Open fullscreen", and put it on the screen you want to test. The values update live — try resizing the window and watch them change. There's nothing to configure.