Stretch a 16:9 video into a 1:1 canvas and everyone turns into pancakes. Aspect ratio is the lock between width and height, and this tool both finds the ratio of any dimensions and scales them to a new width or height without breaking it.
Updated September 03, 2026, after a fresh review, with updated visuals and links.
Find it, then scale by it
Mode one simplifies: 1920x1080 reduces to 16:9 by dividing by the greatest common divisor. It also names the nearest standard (21:9, 16:10, 4:3, 9:16...) when your numbers do not match an exact one.
Mode two preserves: enter a new width (1920x1080 down to 1280 wide) and get the exact proportional height (720). Flip the inputs to scale by height.
The usual suspects: 16:9 for video and slides, 4:5 and 1:1 for feeds, 9:16 for stories and shorts. Mismatches are exactly where black bars and crops come from.
Worth remembering
- Crop first, resize second: reach the target ratio by trimming, not squeezing. A crop keeps pixels honest.
- For thumbnails, compose at the delivery ratio from the start; retrofitting a wide shot into 9:16 always amputates something you wanted.
Frequently asked
What happens if I change only the width?
The image distorts: circles become ellipses and faces stretch. Keeping the ratio locked is the entire point, hence this tool.
Is ultrawide 21:9 compatible with 16:9 video?
It plays letterboxed (black side bars) or cropped (top and bottom lost). There's no perfect conversion because the shapes genuinely differ.
