# Aspect Ratio Calculator Keep an aspect ratio when resizing — enter the original size and one new dimension to get the other, and see the simplified ratio. Runs in your browser. ### How it works The original width and height set the ratio. When you type a new width, the new height becomes `width × (h₁ ÷ w₁)` — and vice-versa — so proportions are preserved exactly. The **aspect ratio** is the width:height reduced by their greatest common divisor (e.g. 1920×1080 → 16:9). All maths runs locally. --- *Source: [ocxly.com/aspect-ratio-calculator.html](https://ocxly.com/aspect-ratio-calculator.html) — OCXLY, free 100% client-side privacy-first tools. Free aspect ratio calculator. Enter an original size and one new dimension to get the other while keeping proportions, and see the simplified ratio, entirely in your browser.*