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Aspect Ratio Calculator

Quick answer: To find an aspect ratio, divide width and height by their greatest common divisor. For example 1920×1080 simplifies to 16:9. To resize, multiply the new width by height ÷ width to get the matching height.

About the Aspect Ratio Calculator

Aspect ratio is the proportional relationship between an image's width and height. Keeping it the same when resizing prevents stretching.

Type in a width and height to see the simplified ratio, then enter a new width or height to get the matching dimension.

How to use it

  1. 1Enter your original width and height.
  2. 2Read the simplified ratio and decimal value.
  3. 3Enter a new width or height to calculate the other side.

Why use this tool

Instant results

Updates as you type.

Two-way scaling

Solve for new width or new height.

Common presets

One click for 16:9, 4:3, 1:1, 9:16 and more.

No upload needed

Pure calculation in the browser.

Frequently asked questions

What is aspect ratio?

It is the ratio of an image's width to its height, written like 16:9. Two images with the same ratio have the same shape even if their sizes differ.

How do I calculate aspect ratio?

Divide both width and height by their greatest common divisor. For 1200×800 the divisor is 400, giving 3:2.

What is the aspect ratio of 1920×1080?

1920×1080 is 16:9, the standard widescreen ratio for HD and Full HD video.

Are my images uploaded to a server?

No. PixTools processes images locally in your browser using your device. Your files are not uploaded or stored.