Screen Resolution
See your display's real resolution, refresh rate and the viewport your browser gives websites.
- Your data never leaves your device
- 100% free
- No sign-up
- Works offline after first load
How to check your screen resolution
- Open the page — your screen details appear instantly.
- Resize the window to see the viewport change.
- Copy the report or run the colour test.
About Screen Resolution
Check your screen resolution in real pixels and CSS pixels, device pixel ratio, browser window and viewport size, aspect ratio, refresh rate, colour depth, HDR and wide-colour support.
Everything works in your browser, so it is instant and private, and your settings are remembered on this device.
Good for
- Choosing wallpapers and screenshot sizes
- Responsive web design and testing
- Checking a new monitor or phone screen
Tip: Turn your phone sideways — orientation and viewport update live.
Frequently asked questions
What is my screen resolution?
The large number at the top is your physical resolution. Below it you see the CSS size the browser uses and the device pixel ratio that links them.
Why is the CSS resolution smaller than my monitor’s?
High-DPI screens and Windows display scaling (125%, 150%) use several physical pixels per CSS pixel. Multiply the CSS size by the pixel ratio to get the real resolution.
What is the viewport?
The part of the browser window that shows the page. Web designers use it for responsive layouts; it changes when you resize the window — try it and watch the numbers update.
How is the refresh rate measured?
By timing the browser’s animation frames for about two seconds, then rounding to the nearest common rate (60, 120, 144 Hz…).
How do I test for dead pixels?
Click “Full-screen colour test” and step through white, black, red, green and blue — stuck or dead pixels stand out against solid colours.