Aspect Ratio Calculator
Find the right dimensions for any aspect ratio. Resize images and videos while keeping the same proportions.
Quick presets
:
Simplified ratio
16 : 9
Preview
16:9
1920 × 1080
What is an Aspect Ratio Calculator?
An aspect ratio calculator works out one dimension when you know the other plus the ratio. Type a new width and the height updates automatically and vice versa, so your image or video keeps the same proportions while you scale it.
FAQs
What aspect ratio should I use for YouTube?
16:9 for standard videos (1920×1080 is the safe upload size). 9:16 for Shorts, usually 1080×1920.
My ratio doesn't round to whole pixels, is that a problem?
The calculator rounds to the nearest integer pixel. A 1-pixel rounding difference is invisible on any normal display.
Does this work offline?
Yes! once the page is loaded, everything runs in JavaScript in your browser.