What Is My Screen Resolution?
Read from your browser. Resize the window and it updates.
Everything below is read from your browser as the page loads.
Three different numbers, all called "resolution"
The panel above shows all three, because confusing them causes real problems.
- Screen resolution — the physical pixels in the panel. What the specification sheet says.
- CSS pixels — what the browser reports to a web page. On a high-density display this is smaller than the physical count, because the operating system is scaling.
- Browser window — the area a page actually gets, once browser chrome, scrollbars and the taskbar have taken their share.
Device pixel ratio
The bridge between the first two. A ratio of 2 means each CSS pixel is drawn using a 2×2 block of physical pixels, so text and graphics are twice as smooth while appearing the same size.
This is why a "retina" laptop reports 1440 × 900 to a web page while having 2880 × 1800 physical pixels. The page is laid out in CSS pixels and rendered at twice the detail.
Ratios are not always whole numbers. Windows scaling at 125 or 150 % gives 1.25 or 1.5, which is a common source of blurry images and half-pixel layout problems.
Design against the window, not the screen
This is the practical lesson. The browser window figure is what a page has to work with, and it is always meaningfully smaller than the screen — often by 100 pixels or more vertically once the browser's own interface is accounted for.
Designing to the screen resolution and discovering the layout is cut off is an avoidable mistake. Resize your window and watch the number change.
What this reveals about you
Worth knowing: every site you visit can read these values, along with your colour depth, time zone, fonts and much else. Combined, they form a browser fingerprint that is often unique enough to identify you across sites without any cookie at all.
An unusual window size makes you more identifiable, not less. This page displays the values and does nothing with them — but the fact that it can is the point.
Common uses
- Reporting a display problem to support.
- Checking scaling is what you expect.
- Testing a responsive layout by resizing.
- Confirming a monitor is running at its native resolution.
Questions people ask
Why does the browser report a smaller resolution than my screen?
Because the operating system is scaling. The device pixel ratio shows by how much — a ratio of 2 means each CSS pixel uses a 2×2 block of real ones.
What is device pixel ratio?
The number of physical pixels per CSS pixel. Above 1 means a high-density display, and the extra pixels go into smoothness.
Why is my browser window smaller than my screen?
Browser chrome, scrollbars and the taskbar all take space. That smaller figure is what a web page actually gets.
Can websites see my screen resolution?
Yes, every site can, along with colour depth and much else. Together these form a browser fingerprint that is often unique.
What causes blurry text after changing scaling?
Fractional scaling such as 125 or 150 % gives a non-integer pixel ratio, which means content cannot land exactly on physical pixels.
Nothing is sent anywhere
The arithmetic runs in the page. Where a tool reads your screen dimensions, it reads what the browser already exposes to every site you visit — and it does not transmit them. The about page lists every request this site makes.