What's My Screen Resolution?

Your screen and browser information is displayed below.

Screen Resolution

Browser Viewport Size

Color Depth

Device Pixel Ratio

About Screen Resolution Checker

Last updated: 25 August 2026

Shows your screen resolution, the size of the browser window, and the pixel density of your display — the three numbers people usually confuse with one another.

Screen, viewport and device pixel ratio

Screen resolution is the whole display. The viewport is the area your web page actually gets, which is smaller — browser chrome, toolbars and scrollbars take the difference. Device pixel ratio is how many physical pixels make up one CSS pixel: 1 on an older monitor, 2 or 3 on a modern phone or Retina screen. A phone reporting 390 px wide really has 1170 physical pixels at a ratio of 3.

Why this matters for images: on a ratio-2 display, an image shown at 400 CSS pixels wide needs an 800-pixel source to look sharp. Serve the 400-pixel version and it appears soft; that is the single most common cause of blurry images on modern screens.

Which number should I design for?

The viewport, always. Media queries, layout breakpoints and readable line lengths all work in CSS pixels, not physical ones. Screen resolution matters only for image assets and for knowing what your audience actually owns.

Why is my window smaller than my screen?

Because the window is not full-screen, or because a system scaling setting is active. Display scaling — 125% or 150% on Windows, the equivalent on macOS — deliberately reduces the CSS pixel count so text stays readable on a dense display. The screen has not changed; the coordinate system has.