Free Aspect Ratio Calculator
Calculate matching proportions and dimensions for video, photos, and web designs.
How to Use Instructions:
- Enter your source dimensions in Original Width and Original Height.
- Type your desired width into the Target Width field.
- The Calculated Height will automatically adjust to preserve the exact aspect ratio.
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About This Tool
Calculate proportional dimensions for images, videos, responsive layouts and other media. Enter known width and height values or a target ratio to determine the missing dimension while preserving the original proportions.
How to Use It
Enter the known dimensions and choose or enter the required aspect ratio. The calculator derives the corresponding dimension without changing the ratio.
How the Calculation or Check Works
An aspect ratio compares width with height. For a ratio of W:H, a matching height for a known width is width × H ÷ W; a matching width for a known height is height × W ÷ H.
Practical Example
A 1920 × 1080 video has a 16:9 aspect ratio. If the width is changed to 1280 while preserving 16:9, the corresponding height is 720 pixels.
Frequently Asked Questions
What is an aspect ratio? It is the proportional relationship between width and height.
Does changing the size change the aspect ratio? Not when both dimensions are scaled by the same proportion.
Where is this useful? Common uses include thumbnails, video exports, social graphics, responsive media and image resizing.