What Is My Screen Size? – Resolution, Inches & Aspect Ratio

What is screen resolution?

Screen resolution is the number of distinct pixels a display can show, expressed as width × height — for example, 1920 × 1080. It determines how much detail and how many elements can fit on screen at once. A higher resolution packs more pixels into the same physical space, producing sharper text and images, provided the display's pixel density is high enough to match.

Resolution is different from screen size. A 15-inch laptop and a 32-inch monitor can both run at 1920 × 1080 — the laptop simply packs those pixels more tightly, resulting in a sharper (higher PPI) image at a smaller physical size.

PPI vs DPI — what's the difference?

PPI (pixels per inch) describes how densely a screen's physical pixels are packed — a property of the display hardware itself. DPI (dots per inch) technically refers to printed output, but the term is commonly, if imprecisely, used interchangeably with PPI when talking about screens.

The tool above estimates your display's diagonal size in inches using your reported resolution and device pixel ratio (DPR), assuming a baseline of 96 DPI. This is an approximation — browsers don't expose the true physical size of a screen, so the estimate can drift on displays with non-standard scaling.

Common screen resolutions

Name	Resolution	Aspect ratio	Typical use
HD	1280 × 720	16:9	Budget laptops, older TVs
Full HD	1920 × 1080	16:9	Most monitors, laptops, TVs
QHD / 1440p	2560 × 1440	16:9	Gaming monitors, high-end laptops
4K UHD	3840 × 2160	16:9	Premium monitors, modern TVs
Ultrawide	3440 × 1440	21:9	Productivity, cinematic gaming

Frequently asked questions

Why does my screen size estimate look off?

Browsers don't report the physical size of a display, so the inch value above is an estimate based on your resolution and device pixel ratio (DPR), assuming a standard 96 DPI baseline. High-DPI displays, like Retina screens, and unusual OS scaling settings can make the estimate less accurate.

What is aspect ratio and why does it matter?

Aspect ratio is the proportional relationship between a screen's width and height, such as 16:9 or 21:9. It affects how much horizontal or vertical space you have for content, and matters when choosing displays for gaming, video editing, or multitasking.

What is DPR (device pixel ratio)?

DPR is the ratio between physical pixels and CSS (logical) pixels on a device. A DPR of 2×, common on high-density displays, means the screen renders twice as many physical pixels per logical pixel, producing sharper text and images without changing the layout size.

Does resolution affect performance?

Yes — higher resolutions require more graphics processing power to render games, videos, and UI elements smoothly. This is why gaming monitors often balance resolution with refresh rate, and why some laptops render at a lower internal resolution before upscaling to the display's native resolution.