Screen Resolution Checker
Check your screen resolution, viewport size, pixel ratio, and display information online.
About this reference
See your screen resolution, viewport size, device pixel ratio, colour depth and orientation live, and refresh after resizing.
Designers and testers use it to confirm what a device actually reports.
How to use it
- Read the values.
- Resize the window or rotate the device.
- Press Refresh Info.
What is measured
The browser reports screen.width × screen.height (your display in CSS pixels), the viewport (innerWidth × innerHeight, the part of the window showing the page), devicePixelRatio, colour depth and orientation. These values come from your own browser; nothing is sent anywhere.
Worked example
Common resolutions
| 1920×1080 | Full HD |
| 2560×1440 | QHD |
| 3840×2160 | 4K UHD |
| 1366×768 | Common older laptops |
| 390×844 | Typical phone, CSS pixels |
Tips and common mistakes
- Page layouts follow the viewport, not the screen.
- Pixel ratio 2 or 3 means a high-density screen.
- Zoom changes viewport size.
- Check both orientations on phones.
- Use media queries for breakpoints.
Frequently asked questions
What is my screen resolution?
The tool shows it above.
What is viewport size?
The visible page area in the browser.
What is device pixel ratio?
Physical pixels per CSS pixel.
Why does it differ from my spec sheet?
Browsers report CSS pixels, scaled by the ratio.
What is colour depth?
Bits per pixel; 24 is standard.
Is data sent anywhere?
No.