Aspect Ratio Calculator β€” resize keeping ratio

Calculate aspect ratios and the missing width or height while keeping the proportion, in your browser.

πŸ”’ Runs entirely in your browser. Your input and output are never sent to a server or stored β€” fully private.

Find the simplified aspect ratio, or lock a ratio and resize to fit.

Common ratios
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About this tool

This calculator works out aspect ratios and resizes dimensions while keeping the same proportion. Enter a known width and height to get the ratio such as 16:9, or lock a ratio and type one dimension to find the other β€” handy for video, images, screens and print layouts. It all runs in your browser.

Frequently asked questions

What is an aspect ratio?

An aspect ratio is the proportional relationship between width and height, written as two numbers like 16:9 or 4:3. It describes the shape regardless of the actual size, so a 1280Γ—720 and a 1920Γ—1080 image are both 16:9.

How do I resize an image without distorting it?

Keep the aspect ratio the same. Enter the original width and height, then change one of them to your target value and the calculator gives the matching dimension that preserves the proportion, so nothing looks stretched or squashed.

Is my data sent anywhere?

No. The calculation runs entirely in your browser, so the dimensions you enter never leave your device.