How Our Tools Work and Where Our Data Comes From

We believe a tool is only as trustworthy as the math behind it, so here's exactly how every calculator on this site works and where our resolution data comes from. Nothing is a black box.

How the screen resolution checker works

The checker reads your resolution directly from your browser, using the standard screen and window properties your device already reports. It shows your screen width and height, device pixel ratio, color depth, and viewport without sending any of it to a server.

Because it reads live values, the result reflects your current display settings, including any scaling. The detection runs entirely in your browser, so your data stays on your device.

How the aspect ratio calculator works

The aspect ratio calculator reduces your width and height to their simplest whole-number form using the greatest common factor (GCF). It divides both numbers by their GCF, so 1920 x 1080 becomes 16:9. When you resize to a fixed ratio, it scales the known side proportionally to find the other.

This is the same method used in design and engineering, which is why our results match standard references exactly.

How the PPI calculator works

The PPI calculator uses the standard pixel-density formula: the diagonal pixel count divided by the diagonal screen size in inches. It finds the diagonal pixel count with the Pythagorean theorem, the square root of width squared plus height squared.

So a 27-inch 1440p screen returns about 109 PPI. The dot pitch we show is simply the inverse of PPI, converted to millimeters.

How the screen size calculator works

The screen size calculator turns a diagonal measurement into real width and height using the aspect ratio and the Pythagorean theorem. For a 16:9 screen, width is the diagonal times about 0.872 and height is the diagonal times about 0.490.

When you add a resolution, it also returns the pixel density, so you get both the physical size and the sharpness in one step.

Where our resolution data comes from

Our pixel dimensions come from the published display standards, including the VESA and DCI specifications and the established consumer naming conventions. We cross-check every figure against multiple references before it goes on the site.

We date each guide with a last-updated stamp, and we review our data when new resolution standards reach the market, such as the 5K2K ultrawide panels that arrived in 2026.

Spotted an error?

We aim for accuracy on every page, but we're human. If a number or formula looks wrong, please tell us through our contact page and we'll review and correct it quickly.