Aspect Ratio Calculator
Resize Without Distortion
Calculate image and video aspect ratios, decimal ratios, and proportional resize dimensions without distortion.
What is this tool?
This aspect ratio calculator simplifies width and height into a ratio such as 16:9, 4:3, or 1:1. It also calculates the proportional missing dimension when resizing an image, video, canvas, or embed.
The ratio is reduced using the greatest common divisor of the width and height. The decimal value is width divided by height, which is useful for layout calculations and responsive containers.
Use it to resize media without stretching, prepare thumbnails, check video formats, calculate social image sizes, or translate design specs into implementation dimensions.
How to use
- Enter the original width and height.
- Read the simplified ratio and decimal ratio.
- Enter a new width to calculate matching height, or a new height to calculate matching width.
- Copy the ratio when documenting image, video, or layout specs.
Examples
| Input / setting | Output | Notes |
|---|---|---|
1920 x 1080 | ratio 16:9; decimal 1.7778 | Standard widescreen video. |
1080 x 1080 | ratio 1:1; decimal 1.0000 | Square image. |
original 1920 x 1080; new width 1280 | new height 720.00 | Resize without distortion. |
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Last reviewed: 2026-05-08