Aspect Ratio Calculator
Calculate aspect ratios, find missing image or video dimensions, and verify proportions for common formats like 16:9, 4:3, and 1:1.
Embed this Tool on Your Website
Copy this code snippet to add the Aspect Ratio Calculator to your blog or website for free. It adjusts dynamically to mobile and desktop screens.
How to Use Aspect Ratio Calculator
Aspect Ratio Calculator Formula / How It Works
The calculator finds the Greatest Common Divisor (GCD) of the two input values using the Euclidean algorithm and divides both by it to produce the simplest whole-number ratio. Missing dimensions are found by multiplying the known dimension by the inverse ratio.
For example, entering 1920 × 1080 produces a ratio of 16:9. Entering a target of 1280 × 720 confirms the proportions match at 16:9 with a scale factor of 0.67×.
Frequently Asked Questions
An aspect ratio is the proportional relationship between a rectangle's width and height, expressed as width:height (e.g., 16:9, 4:3). It matters for video production, web design, and photography because it determines how content is displayed on different screens without distortion.
Enter the original width and height, then enter either the new width or new height. The calculator automatically computes the missing dimension to preserve the original ratio. New width = original width × (new height / original height).
16:9 is the standard for HD/4K video, YouTube, and most modern monitors. 4:3 is the legacy TV format. 1:1 is used for Instagram posts. 9:16 is portrait video for mobile (Reels, TikTok, Shorts). 21:9 is used for ultrawide cinema and monitors.
Yes. Enter your base dimensions (e.g., 1920 × 1080) and calculate proportional sizes for smaller breakpoints. This is useful for maintaining consistent media sizing across different viewport widths.
No. All calculations run locally in your browser. No data is transmitted to any server or stored anywhere.
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