Free aspect ratio calculator
Enter a width and height to get the simplest aspect ratio, such as 1920 x 1080 = 16:9. Or choose a ratio and one side to find the other.
What is the ratio of my picture?
Find the missing side
Height is 675 px (1200 x 675)
Free, no sign-up, nothing to install.
What is an aspect ratio?
An aspect ratio is the relationship between the width and the height of a picture or screen, written as two numbers. 1:1 is a square, 4:5 a slightly tall portrait, 9:16 a tall phone screen and 16:9 the wide shape of most video. The ratio stays the same however big the picture is: 1920 x 1080 and 1280 x 720 are both 16:9.
Knowing the ratio lets you resize without squashing. If you have a 16:9 picture that must be 1200 pixels wide, the height is 675. Choose the ratio and the side you know and the tool gives you the other.
How to find an aspect ratio
- Type the width and the height of your picture in pixels.
- Read the simplest ratio. If it is not a clean one, the nearest common ratio is shown.
- To find a missing side, choose the ratio you want to keep, say whether you know the width or the height, and type it.
Questions people ask
How do I calculate an aspect ratio?
Divide the width and the height by their greatest common divisor. For 1920 x 1080 that number is 120, which gives 16 and 9, so the ratio is 16:9.
What aspect ratio is a phone screen?
Most phones are close to 9:19.5 or 9:20 when held upright. Stories and Reels use 9:16.
What is the ratio of an Instagram post?
Portrait posts are 4:5 (1080 x 1350), square posts 1:1 (1080 x 1080).
How do I resize without distorting?
Keep the same aspect ratio. Change the width and work out the height from the ratio, or use the image resizer with Keep the shape ticked.