Free Screen Resolution Checker
See your screen size, window and device info.
What is the Screen Resolution Checker?
'What's your screen resolution?' is one of the first questions in any tech support or design conversation, and most people have no idea. This checker answers it and a lot more the moment you open it: your screen resolution, the actual browser window size, the device pixel ratio, colour depth, orientation, and which browser and operating system you're on.
Everything is read from your own device and shown only to you — nothing is uploaded.
Last updated: Aug 27, 2026
What does this tool do?
It reads the display and browser details your device already exposes and lays them out in a clear table. The headline shows your live browser-window size, which updates as you resize the window, while the table lists the full screen resolution, available area, device pixel ratio, actual pixel count, colour depth, orientation, browser and OS.
It's a read-only snapshot — it changes nothing on your device.
Key features
Screen resolution
Your display's full width and height.
Live window size
The browser viewport, updating as you resize.
Device pixel ratio
How many physical pixels each CSS pixel maps to.
Browser & OS
Detected from your browser automatically.
Private
Read from your device and shown only to you.
Example
Common use cases
- Web developers — Check viewport size and pixel ratio while testing.
- Designers — Confirm the resolution a layout must fit.
- Support agents — Ask a user to read off their screen details.
- QA testers — Record device specs for a bug report.
- Gamers — Verify a monitor's resolution and colour depth.
- Anyone — Answer 'what's my screen resolution?' instantly.
Benefits
- Every detail in one place, no digging through settings.
- The window size updates live as you resize.
- Nothing is installed or uploaded.
- Free and instant.
Tips
- Note the difference between screen resolution (your whole display) and the browser window (just the tab area).
- A device pixel ratio above 1 means a high-DPI display — design assets at that multiple to stay crisp.
- Resize the window and watch the viewport figure to test responsive breakpoints.
- Share the full table with a support agent so they have your exact setup.
- Actual pixels = resolution × pixel ratio, which is why a 'Retina' screen reports more than its logical size.
Common mistakes to avoid
Confusing window size with screen resolution
Fix: The window is just the browser; the resolution is the whole display.
Ignoring device pixel ratio
Fix: On high-DPI screens, CSS pixels aren't physical pixels — the ratio explains the gap.
Assuming everyone shares your resolution
Fix: Test at several window sizes; visitors' screens vary widely.
Worrying the data is sent somewhere
Fix: It isn't — everything is read locally and shown only to you.
How it works
- 1
Open the tool
It reads your device details.
- 2
Read the specs
Resolution, DPR, colour depth and more.
- 3
Resize to test
The window size updates live.
Frequently asked questions
Screen resolution is your whole display; the window size is just the browser window, which updates live as you resize it.
No — everything is read from your browser and shown only to you.
Screen resolution is your whole display; the window size is just the browser window, which updates live as you resize it.
No — everything is read from your browser and shown only to you.
It's how many physical pixels map to one CSS pixel. A ratio above 1 means a high-DPI ('Retina') display.
Yes, completely free with no sign-up.
Conclusion
One glance gives you your screen resolution, live window size, pixel ratio, colour depth, browser and OS — everything read straight from your own device. It's the fastest way to answer a support question or check a display's specs, with nothing uploaded.