Calculators

Aspect Ratio

Reduce a width and height to a clean aspect ratio and solve the matching height for any new width. Ideal for resizing images and video without distortion.

Try it now

Worked example

Ratio: 16:9 · New height: 720

How it’s solved

Worked on the example above, step by step — follow along and you can do it on paper next time, no tool required.

Aspect ratio is width-to-height in lowest terms; keeping it fixed lets you resize without stretching.
Reduce width : height by their GCD
1920 : 1080 ÷ 120 = 16 : 9
Solve the matching height: new width × height ÷ width
1280 × 1080 ÷ 1920 = 720

Learn the method

Inputs

Width
1920
Height
1080
New width
1280

Frequently asked

What is 1920 × 1080 reduced?

16:9 — the standard widescreen ratio.

How do I keep proportions when resizing?

Enter the original size and a new width; the tool returns the height that preserves the ratio.