Aspect Ratio Calculator
Find the aspect ratio of any size and scale dimensions proportionally.
Find the simplified aspect ratio of any width and height (like 16:9) and scale dimensions proportionally. Enter an original size and, optionally, a new width to get the matching height that preserves the ratio — essential for images, video and responsive layouts where stretching looks wrong.
It runs in your browser and shows both the ratio and the decimal value.
Frequently asked questions
How do I calculate an aspect ratio?
Enter the width and height; the tool divides both by their greatest common divisor to give a ratio like 16:9.
How do I resize without distortion?
Enter your original size plus the new width, and the tool gives the height that keeps the same proportions.
What is 16:9?
The standard widescreen ratio for most videos and monitors — 16 units wide for every 9 tall.
Why do proportions matter?
Changing width and height independently stretches or squashes an image. Keeping the aspect ratio avoids distortion.