Aspect Ratio Calculator

Calculate aspect ratios, resize dimensions proportionally, and visualize common ratios like 16:9 and 4:3. Instant copy.

How It Works

1

Enter a dimension

Type a width or height in pixels. The tool calculates the other dimension when you select a ratio.

2

Pick or calculate a ratio

Click a preset ratio (16:9, 4:3, etc.) or enter both dimensions to see the simplified ratio.

3

Copy and use

Copy the ratio string or the calculated dimensions for your design, video, or responsive layout.

FAQ

The tool finds the greatest common divisor (GCD) of width and height to reduce them to the smallest whole-number ratio.
16:9 is the standard for monitors, TVs, and YouTube. 9:16 is standard for mobile/vertical video. 4:3 is common for older displays and presentations.
Yes. Enter your image dimensions to find the ratio, or pick a ratio and one dimension to calculate the other. Great for cropping, thumbnails, and responsive images. For generating placeholder images, try the image placeholder generator.

Built & Maintained by Varstatt

Varstatt is a one-person product studio run by Jurij Tokarski, product engineer since 2011. These tools are free and open — no signup, no catch.