Calculate aspect ratios for images, videos and screens. Scale dimensions perfectly.
This tool is currently under development. We're working hard to bring it to you — it'll be worth the wait!
An aspect ratio calculator works out the correct width or height to keep an image, video, or screen proportional when resizing — so your content doesn't come out stretched or squished. Enter your original dimensions and either a new width or height, and it calculates the matching value that keeps the ratio intact.
Resizing an image or video without locking the aspect ratio is a fast way to end up with distorted, unprofessional-looking content. This tool exists so designers, editors, and anyone resizing media can get the exact matching dimension without trial and error.
The calculation is based on cross-multiplication: if the original ratio is Width₁:Height₁, then a new Width₂ needs a matching Height₂ such that Width₁ ÷ Height₁ equals Width₂ ÷ Height₂. So resizing a 1920×1080 image (a 16:9 ratio) down to a width of 1280 gives a matching height of 720 — keeping the exact same proportions at a smaller size.
Aspect ratio is the proportional relationship between an image or screen's width and height, commonly expressed like 16:9 or 4:3.
Keep the same ratio between width and height as the original — this calculator finds the correct matching dimension for you automatically.
16:9 is a widescreen format common in modern video and displays, while 4:3 is the older, more square format used in older TVs and some print media.
Yes, the same ratio math applies whether you're working in pixels for screens or inches/centimeters for print.
Yes, it's commonly used when resizing or cropping video to fit different platforms while keeping the footage from looking stretched or squeezed.