# Aspect Ratio Calculator

## Calculate the aspect ratio to match any custom width and height combination.

### 16:9 Ratio Calculator

Width: px / cm / inch
Height: px / cm / inch

## Understanding ratio 16:9

A 16:9 ratio (also pronounced “16 9”, “16 to 9”, or “16 by 9” and sometimes written as “16x9”) is an aspect ratio, where for every 16 units of width, there are 9 corresponding units of height. Examples of 16:9 ratios are 16 inches wide by 9 inches high, 32 widgets wide by 18 widgets high, and 1920 pixels wide by 1080 pixels high. An image has a 16:9 ratio if its width-to-height ratio is equal to 16/9, or 1.78. A 16:9 ratio can also be represented as 1.78:1. 16:9 is significant because it is today’s standard ratio for film and display. The 16:9 ratio replaced the old 4:3 ratio in the early 2,000s. You may have heard terms such as 1080p HD, 720p HD, and 4K UHD. These terms all refer to 16×9 ratios. For example, a 1080p HD display refers to a screen resolution of 1920x1080p (1920/1080 = 1.78).

## How to use?

### How to calculate a Custom Size

1. Insert the first value (width or height).
2. Select a preset, or insert the other value.

### How to calculate a HD / FHD / 4K aspect ratio

1. Select a preset from the list, for example 5:3 aspect ratio.
2. Insert one of the values: width or height.

## About Aspect Ratio Calculator

The aspect ratio of an image defines the proportion between its width and height. It is always expressed as two numbers separated by a colon `x:y`.

For example, images with an aspect ratio of 4:3 will always have a width of 4 units and a height of 9 units of the same length. This is easy to understand when the numbers are simple: an image of 1600x900 pixels has an aspect ratio of 16:9, or an image of 3000x1500 has an aspect ratio of 2:1.

But it is more complicated when the numbers do not round to anything known, for example with Social Media sizes used by Facebook, Instagram, or Twitter, an image of 1200x628px needs to have an aspect ratio of 1.91:1.

We use a complicated formula that rounds in special cases to give a human-understandable fraction to achieve results. For example, when the left unit of the formula results in 8 units and the right unit results in 5 units, instead of using the mathematical value of 8:5 is standard to convert it to 16:10.