Aspect Ratio Calculator — free online tool
You have one side of an image or video and need the other, but the ratio has to stay right so nothing looks stretched. Doing that math in your head is annoying, and a wrong guess means redoing the whole thing. We added a free tool that does it for you — Aspect Ratio Calculator — right in your browser.
What it does
Type in a width or a height, pick a ratio, and it gives you the other dimension straight away. It comes with the common presets people use most — 16:9, 4:3, and 1:1 — and if your project needs something different, you can enter your own ratio by hand. The result updates as you go, so you can try a few sizes without starting over.
Nothing leaves your device
The whole thing runs in your browser. The numbers you type stay on your screen — nothing is uploaded to a server and nothing is saved anywhere. Close the tab and it's gone.
How to use it
- Open Aspect Ratio Calculator and type in the width or height you already have.
- Pick a preset like 16:9, or enter your own ratio.
- Read off the matching dimension and use it.
It's free with no limit. There are more small tools on the Apps page.