← Everyday Tools HubScreen Size Lab
screen size labDIMENSIONS, EXPLAINED.Compare your next screen

THE TOOLKIT / 01

Screen dimensions & PPI

Calculate active width, height, area and pixel density from diagonal, aspect ratio and resolution.

Free to use · All calculations stay in your browser

ENTER YOUR MEASUREMENTS

Physical aspect ratio

These two values control the physical shape. Presets set an exact match to the resolution; custom inputs are checked for a mismatch.

Runs locally. Your numbers stay in this browser.

ACTIVE PICTURE · TO A COMMON SCALE

YOUR RESULT

—

Enter your numbers to make a measurement.

Flat active-picture geometry. Outer housings, curvature, stands and software scaling are not modeled.

Physical aspect fields control geometry. Pixel fields control density. A mismatch greater than 0.1% is flagged; directional densities are shown instead of one square-pixel PPI. Exact manufacturer viewable dimensions take priority over this geometric estimate.

THE MATH, IN PLAIN SIGHT

How it works.

width = diagonal × aspect width ÷ √(aspect width² + aspect height²). Height uses aspect height instead. Area = width × height. Horizontal PPI = horizontal pixels ÷ width in inches; vertical PPI uses height.

A worked example

For a 27 inch 16:9 active rectangle with 2560 × 1440 pixels: width ≈ 23.53 in, height ≈ 13.24 in, area ≈ 311.50 in², density ≈ 108.8 PPI.

A LITTLE MORE CONTEXT

Understand what
the number means.

The number on the box runs from one corner of the active picture to the opposite corner. To understand the shape in front of you, add the aspect ratio—and keep the screen separate from its housing.

Read the field note