What this page shows
- Screen resolution – the size of your screen in CSS pixels, the unit websites use for layout.
- Physical pixels – the real number of pixels on the panel. On phones, tablets and high-DPI laptops (such as Retina displays) this is higher, because each CSS pixel is drawn with several physical pixels.
- Device pixel ratio – how many physical pixels make up one CSS pixel. Windows display scaling of 125% or 150% shows up here as 1.25 or 1.5.
- Viewport – the size of the visible area inside your browser window. Resize the window and watch it change.
Everything is read directly from your browser. Nothing is sent to a server, and the page cannot see anything you don’t see here.
Common screen resolutions
| 1366 × 768 | Older and budget laptops (HD) |
|---|---|
| 1920 × 1080 | Full HD – the most common desktop monitor and laptop resolution |
| 2560 × 1440 | QHD / 1440p – popular for gaming and office monitors |
| 3840 × 2160 | 4K UHD – TVs and high-end monitors |
| 390 × 844, 393 × 852 | Typical modern iPhones (in CSS pixels) |
| 360 × 800, 412 × 915 | Typical Android phones (in CSS pixels) |
FAQ
Why does my 4K monitor show 2560 × 1440 or 1920 × 1080?
Your operating system is scaling the display (for example 150% or 200%) so text isn’t tiny. The Physical pixels row shows the real resolution.
Why do web developers need this?
Knowing the viewport size and pixel ratio helps when testing responsive layouts, choosing image sizes, and reproducing bugs reported by users. Click Copy all details to paste everything into a bug report.