Aspect Ratio Calculator
Find the ratio of any width and height, or calculate matching dimensions without stretching your image, video or design.
Find an Aspect Ratio
Enter the original width and height.
Resize Without Stretching
Choose a common ratio or enter your own.
Need to resize an image, video or layout without making it look stretched? Enter the dimensions to find the aspect ratio, or choose a ratio and calculate a matching width or height.
About This Tool
Aspect ratio describes the relationship between width and height. A 16:9 ratio, for example, means the width is 16 units for every 9 units of height.
The actual size does not matter as long as the proportions stay the same. That is why 1920 × 1080, 1280 × 720 and 640 × 360 all share the same 16:9 aspect ratio.
This calculator can reduce a pair of dimensions to its simplest ratio and can also help you resize something while keeping its original proportions. It is useful for images, videos, thumbnails, screens, website layouts and other visual work where stretching or squashing the content would be noticeable.
How to Use
- Enter a width and height in the first section to find their simplified aspect ratio.
- If you already know the ratio you want to use, choose one of the common presets or enter your own ratio. Then type a new width or height. The other dimension is calculated automatically so the proportions stay the same.
- Use Swap Ratio when you want to reverse the orientation. For example, 16:9 becomes 9:16.
Example
A 1920 × 1080 image reduces to a 16:9 aspect ratio.
If you want to resize it to 1280 pixels wide, keep the ratio at 16:9 and enter 1280 as the new width. The matching height is 720 pixels, so the resized image becomes 1280 × 720 without changing its proportions.
Frequently Asked Questions
What is an aspect ratio?
An aspect ratio compares the width of something with its height. A ratio of 16:9 means that for every 16 units of width there are 9 units of height.
How do I calculate an aspect ratio from width and height?
Reduce the width and height by their greatest common divisor. For example, 1920 and 1080 can both be divided by 120, giving the simplified ratio 16:9.
What is the aspect ratio of 1920 × 1080?
1920 × 1080 has a 16:9 aspect ratio. The same ratio is also used by dimensions such as 1280 × 720 and 3840 × 2160.
What is the difference between 16:9 and 9:16?
They use the same proportions in different orientations. 16:9 is landscape, while 9:16 is portrait and is commonly used for vertical video and mobile content.
Does changing the resolution change the aspect ratio?
Not necessarily. You can change the resolution while keeping the same aspect ratio. For example, 1920 × 1080 and 1280 × 720 are different resolutions but both are 16:9.
Why does an image look stretched after resizing?
Stretching usually happens when the width and height are changed independently. Keeping the same aspect ratio preserves the original proportions.