Screen resolution vs. browser window size
Screen resolution is the number of physical pixels on the display, such as 1920 × 1080 on a Full HD laptop or 1440 × 3120 on a Galaxy S25 Ultra. CSS pixels (the screen size websites see) are larger, because phones and high-resolution laptops scale everything up so text stays readable. The device pixel ratio is how many physical pixels make up one CSS pixel. Physical resolution = CSS size × pixel ratio.
Why the resolution may look lower than advertised
- Display scaling: Windows set to 125% or 150% makes websites see fewer CSS pixels. The physical resolution line on this page accounts for that.
- Phone resolution settings: Samsung Galaxy phones often run at FHD+ by default to save battery. Change it in Settings › Display › Screen resolution.
- Browser zoom: zooming in or out changes the pixel ratio. Press Ctrl + 0 (⌘ + 0 on Mac) to reset zoom before measuring.
- External monitors: the browser reports the screen the window is on. Move the window to measure another monitor.
Common screen resolutions
- HD: 1280 × 720 · Full HD (1080p): 1920 × 1080 · QHD (1440p): 2560 × 1440 · 4K UHD: 3840 × 2160
- MacBook Air 13" (M-series): 2560 × 1664 · MacBook Pro 14": 3024 × 1964
- iPhone 16: 1179 × 2556 · iPhone 16 Pro Max: 1320 × 2868
Pixel density (PPI): why sharpness isn’t just resolution
The same resolution looks sharper on a smaller screen. Pixel density, in pixels per inch (PPI), is the diagonal pixel count divided by the screen size in inches. A 24-inch 1080p monitor is about 92 PPI, a 27-inch 1440p monitor about 109 PPI, a 14-inch 1080p laptop about 157 PPI, and most current phones are between 400 and 500 PPI. At a normal viewing distance, around 110 PPI looks sharp on a desktop monitor, around 200 on a laptop and around 300 on a phone.
Which resolution do you need?
- Laptops 13 to 15 inches: 1920 × 1080 is fine for most work; 2560 × 1600 or higher makes text noticeably crisper.
- 24-inch monitors: 1080p. 27-inch: 1440p for sharpness, 4K for photo and design work. 32-inch and up: 4K.
- Gaming: a higher refresh rate often matters more than resolution. Check yours with the refresh rate test.
- Buying a used phone or laptop: compare the physical resolution here with the model’s spec. A lower number than advertised, with scaling at 100% and zoom reset, can mean a cheaper replacement screen was fitted.
Want to check the display itself? Try the dead pixel test, the refresh rate test, or the full phone or laptop diagnostic.
Frequently asked questions
How do I find my screen resolution?
This page shows it instantly. On Windows you can also open Settings › System › Display › Display resolution, on a Mac System Settings › Displays, and on Samsung phones Settings › Display › Screen resolution.
Why is my screen resolution different from my browser size?
Phones and high-resolution laptops scale the screen so text isn’t tiny. Websites see CSS pixels, and each CSS pixel is made of several physical pixels. The device pixel ratio tells you how many.
What is device pixel ratio?
It is the number of physical pixels per CSS pixel in each direction. A ratio of 3 means a 412 × 915 CSS screen has 1236 × 2745 physical pixels. Browser zoom and display scaling change it.