Aspect Ratio Calculator

The Aspect Ratio Calculator is a free tool that instantly computes the proportional relationship between the width and height of any object, image, or video frame. Enter any width or height, and the calculator automatically simplifies the ratio to its lowest terms. Whether you want to calculate aspect ratio from width and height in pixels, inches, cm, or meters, you'll always know the exact shape of your content.

Whether you're preparing a YouTube thumbnail at 16:9, cropping an Instagram post to 4:5, or designing a banner at a custom ratio, this calculator helps you find equivalent dimensions without guesswork. All calculations happen instantly in your browser — nothing is uploaded or stored.

Content creators juggle dozens of dimension requirements across platforms. A YouTube video needs 16:9, an Instagram Reel needs 9:16, and a LinkedIn banner needs 1584×396 — which is actually 4:1. Memorizing all of these is impractical.

This calculator eliminates trial-and-error resizing. Lock a ratio, change one dimension, and the other adjusts automatically. Designers use it to verify client mockups. Video editors use it to double-check export settings. Social media managers use it to ensure every post fits perfectly, the first time.