ToolStack

Aspect Ratio Calculator

Resize an image or video while keeping its aspect ratio exactly intact.

100% private — everything runs in your browser

How to Use

  1. 1

    Type the ratio you need, for example 16:9 or 4:3.

  2. 2

    Enter the width or height you already know.

  3. 3

    Read the matching dimension and copy it into your editor.

Examples

Full HD width

Input

Ratio 16:9 · width 1920

Output

The matching height is 1080.

Square crop

Input

Ratio 1:1 · height 800

Output

The matching width is 800.

FAQ

Does it round the result?

Yes. Dimensions are rounded to whole pixels, because browsers and video encoders expect integers.

Can I keep a ratio while fitting a maximum size?

Enter the limiting side as the known value and the other side will scale proportionally.

Why does my video look stretched?

The source ratio and the target ratio disagree. Use this tool to compute the matching side before resizing.

Related Tools

Image ResizerResize images to exact dimensions while keeping aspect ratio — right in your browser.Image CropperCrop images to exact dimensions with preset aspect ratios — right in your browser.Pixels to REMConvert pixels to rem instantly, with a table for the values people look up most.Age CalculatorCalculate exact age in years, months, days and more — right in your browser.Percentage CalculatorCalculate percentages in multiple modes: X% of Y, X is what % of Y, and percent change.BMI CalculatorCalculate your Body Mass Index instantly with metric and imperial units.