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Aspect Ratio Calculator

Calculate the aspect ratio from a width and height, or work out a dimension from a ratio.

Input data is processed in your browser
Data is never sent to a server

Tool

16 : 9
Decimal ratio: 1.7778

Using the ratio calculated above, find the matching value for a target width or height.

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What is the Aspect Ratio Calculator?

The Aspect Ratio Calculator calculates the aspect ratio from a width and height. It includes presets for common ratios like 16:9, 4:3, and 1:1, a lock feature that keeps values in sync with the current ratio, and a reverse calculator that finds a matching dimension from a target size.

No image upload is needed — all calculations happen entirely in your browser.

Use Cases

  • Design a video or banner ad to fit a specific aspect ratio
  • Calculate the matching height or width before resizing an image to a target ratio
  • Quickly check a display's or camera's aspect ratio

How to Use

  1. Enter a width and height in pixels. Turn on the lock icon to keep the ratio fixed when changing one value.
  2. Use presets like 16:9, 4:3, or 1:1 to quickly set common ratios.
  3. The simplified ratio (e.g. 16:9) and decimal ratio are shown automatically.
  4. In the "Find a dimension from the ratio" section, enter a target width or height to calculate the matching value for that ratio.

FAQ

Is this tool free?

Yes, it is completely free to use. No image upload is required.

How is the ratio calculated?

The greatest common divisor of the width and height is found and used to divide both, producing the simplest integer ratio.

How does the reverse calculation work?

Based on the ratio calculated above, entering a "target width" shows the matching height, and entering a "target height" shows the matching width.

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