Aspect Ratio Calculator & Resolution Scaler

Find the ratio of any resolution, resize while keeping proportions, scale by percentage, or fit to a bounding box.

Original width (px)

Original height (px)

Ratio:

New width (px)

New height (px)

Lock aspect ratio

Scale: %

Max width (px)

Max height (px)

Frequently asked questions

How do I calculate an aspect ratio from a resolution?: Divide both the width and height by their greatest common divisor. For example, 1920×1080 simplifies to 16:9. This tool does it automatically as you type.
How do I resize an image while keeping the aspect ratio?: Enter your original width and height, then type the new width — the new height is calculated automatically so the proportions stay identical (no stretching).
What is the difference between scaling and fitting?: Scaling multiplies both dimensions by the same percentage. Fitting shrinks the image just enough to fit inside a maximum width and height while preserving the ratio.