ToolWren › Aspect Ratio

Aspect Ratio Calculator

Resize images or video without distortion. Enter the original width and height, then type a new width or height and the other value is calculated to preserve the ratio.

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How to use the Aspect Ratio

Enter the original width and height.
Type a new width to get the matching height, or a new height to get the width.
The simplified aspect ratio (like 16:9) is shown automatically.
Use the values to resize images or video without distortion.

Privacy: this tool runs entirely in your browser. Your input is never sent to, received by, or stored on any server — there are no uploads and no tracking of what you enter.

About Aspect Ratio

What is an aspect ratio?

An aspect ratio expresses the proportional relationship between width and height, like 16:9 or 4:3. Keeping it constant when resizing prevents stretching or squashing.

Solving for the missing side

Given the original dimensions and one new side, the other is found by simple proportion: newH = newW × origH ÷ origW. The tool also shows the simplified ratio using the greatest common divisor.

Common ratios

16:9 (widescreen video), 4:3 (classic displays), 1:1 (square social posts), 9:16 (vertical/stories) and 3:2 (photography) are the ones you'll meet most often.

Frequently asked questions

How is the simplified ratio calculated?

By dividing both dimensions by their greatest common divisor — so 1920×1080 simplifies to 16:9.

Can I go from height to width?

Yes — fill in the new height and the new width is computed, or vice-versa.

Does it round to whole pixels?

Yes, computed dimensions are rounded to the nearest pixel.