Aspect Ratio Calculator

The aspect ratio is the proportion between width and height. Enter the original size to see the simplified ratio, then type a new width or height and the other side is calculated so the image does not stretch.

Common ratios

Original size

New size (type one side and the other follows)

Aspect ratio
Width ÷ height

Runs entirely in your browser. Nothing you enter is sent to a server.

How to use it

  1. Enter the original width and height, or press a common ratio.
  2. Read the simplified aspect ratio.
  3. Type the new width, or the new height, in the resized fields.
  4. Use the calculated value for the other side.

Common ratios

  • 16:9: widescreen video, YouTube, most monitors and TVs.
  • 4:3: older screens, many tablets and some cameras.
  • 1:1: square posts and profile pictures.
  • 3:2: classic photography (35 mm film and many cameras).
  • 9:16: vertical video such as Stories, Reels and Shorts.
  • 4:5: portrait posts on Instagram.
  • 21:9: ultrawide monitors and cinema.

Frequently asked questions

How is the ratio simplified?
Both numbers are divided by their greatest common divisor. For example, 1920 x 1080 becomes 16:9.
What if my numbers are not whole?
The tool then shows the ratio as a decimal such as 1.778:1, because a ratio with fractions cannot be simplified.
How do I resize without distorting an image?
Change only one side and calculate the other with the same ratio. Cropping is the other option if you need a different ratio.
Why are the results rounded?
The new size is calculated with up to two decimals. For pixels, round it to the nearest whole number.

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