Aspect Ratio Calculator

WebToola

Simplify integer dimensions to a ratio and optionally scale to a target width. Dimensions must be positive whole numbers.

About the Aspect Ratio Calculator

The Aspect Ratio Calculator helps you find the simplified ratio between a width and height. Enter two positive whole-number dimensions and the calculator will determine the aspect ratio and its decimal value.

You can also enter an optional target width to calculate new dimensions while maintaining the original aspect ratio. This is useful when resizing images, videos, screens and other visual content without changing their proportions.

How to Use the Aspect Ratio Calculator

Enter the original width and height of your image, video, screen or other content. If you only need to find the aspect ratio, leave the target width empty and select Calculate.

To scale the dimensions, enter a target width as well. WebToola will calculate the corresponding height needed to preserve the original aspect ratio.

For example, using:

Original width: 1920
Original height: 1080
Target width: 1024

produces:

Aspect ratio: 16:9
Decimal ratio: 1.77777777778
Scaled dimensions: 1024 × 576

This means a 1920 × 1080 image can be resized to 1024 × 576 while retaining the same 16:9 proportions.

How Is Aspect Ratio Calculated?

An aspect ratio describes the proportional relationship between width and height. It is commonly written as two numbers separated by a colon, such as 16:9, 4:3 or 1:1.

To simplify an aspect ratio, the width and height are divided by their greatest common divisor (GCD).

For a 1920 × 1080 image:

GCD of 1920 and 1080 = 120

Then:

1920 ÷ 120 = 16
1080 ÷ 120 = 9

So the simplified aspect ratio is:

16:9

The decimal ratio is calculated by dividing the width by the height:

1920 ÷ 1080 ≈ 1.7778

When scaling to a new width, the corresponding height is calculated so that the same proportions are maintained.

Common Uses for Aspect Ratios

Aspect ratios are commonly used when working with images, videos, displays, presentations and web layouts. Maintaining the correct ratio helps prevent visual content from appearing stretched or compressed.

For example, 16:9 is widely used for widescreen video and displays, while 1:1 represents a square. An aspect ratio calculator is particularly useful when you know the dimensions of the original content but need to resize it to a different width without changing its proportions.

Frequently Asked Questions

What is an aspect ratio?

An aspect ratio describes the proportional relationship between the width and height of an image, video, screen or other rectangular area. For example, 1920 × 1080 simplifies to an aspect ratio of 16:9.

How do I calculate an aspect ratio?

Divide both the width and height by their greatest common divisor. For example, dividing 1920 and 1080 by 120 gives 16 and 9, resulting in a 16:9 aspect ratio.

What does a 16:9 aspect ratio mean?

A 16:9 aspect ratio means that for every 16 units of width, there are 9 units of height. The actual dimensions can vary—for example, both 1920 × 1080 and 1280 × 720 have a 16:9 aspect ratio.

How do I resize an image without changing its aspect ratio?

Keep the width and height proportional when resizing. Enter your original dimensions and a new target width into the calculator, and it will calculate the corresponding height needed to maintain the original aspect ratio.

Does WebToola store the dimensions I enter?

No. The Aspect Ratio Calculator runs in your browser and does not send or save the dimensions you enter.