Aspect Ratio Calculator
Convert between an aspect ratio and exact pixel dimensions, fit a ratio inside a bounding box, or find the largest crop that matches a target ratio — all client-side.
Converts a ratio like 16:9 or 4:5 into exact pixel dimensions at whatever base size you need, or works the other way — enter pixel dimensions and get the simplified ratio back. A quick reference for anyone specifying image or video dimensions without doing the math by hand.
How to use it
Enter a known ratio and one target dimension (e.g. “16:9, width 1920”) to get the matching height, or enter exact pixel dimensions to see the simplified ratio they reduce to.
FAQ
What’s this useful for? Common when prepping export dimensions for a specific platform’s required ratio — social posts, video formats, or print sizes — without manually calculating the matching side.
Does it handle less common ratios, not just 16:9 and 1:1? Yes, enter any ratio, standard or custom, and it calculates dimensions the same way.
Can I go from pixels back to the simplified ratio? Yes, entering exact width and height returns the reduced ratio those dimensions represent.