Screen resolution vs native resolution
Browsers report sizes in CSS pixels, which already include your operating system's display scaling. That is why a 4K laptop may show 1536 × 864 here. Multiply by the device pixel ratio to estimate the native panel resolution: 1536 × 864 at a ratio of 2.5 is 3840 × 2160.
Common resolutions
| Name | Resolution | Aspect ratio |
|---|
| HD | 1280 × 720 | 16:9 |
| Full HD (1080p) | 1920 × 1080 | 16:9 |
| QHD (1440p) | 2560 × 1440 | 16:9 |
| 4K UHD | 3840 × 2160 | 16:9 |
| Ultrawide QHD | 3440 × 1440 | 21:9 |
| MacBook Air 13" (scaled) | 1470 × 956 | about 16:10 |
Testing a display? Check for stuck pixels with the dead pixel test, measure frame rate with the FPS test, or see your browser details with what is my browser.
Last reviewed October 2026.
Frequently asked questions
What is my screen resolution?
The big number at the top is your screen resolution as your browser reports it, in CSS pixels. The "physical pixels" value multiplies it by your device pixel ratio, which is usually your display's real native resolution.
Why is my screen resolution smaller than my monitor's spec?
Operating systems scale the display so text isn't tiny. A 4K (3840 × 2160) monitor at 150% scaling reports 2560 × 1440 to websites, with a pixel ratio of 1.5. Multiply by the pixel ratio to get the native resolution.
What is the difference between screen size and window size?
Screen size is your whole display. Window (viewport) size is the area inside your browser where the page is drawn, which is smaller because of toolbars, tabs and the taskbar. Resize the window and watch it update live.
What is device pixel ratio?
The number of physical screen pixels per CSS pixel. Standard monitors are 1, many laptops are 1.25 to 2, and phones are often 2 or 3. A higher ratio means sharper text and images.
What are the most common screen resolutions?
For desktops, 1920 × 1080 is still the most common, followed by 1366 × 768, 1536 × 864 and 2560 × 1440. Phones commonly report widths of 360 to 430 CSS pixels.