Aspect Ratio Calculator
Simplify a width and height to its aspect ratio, or solve a missing dimension.
- Aspect ratio
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- Decimal
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- Dimensions
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What is an aspect ratio?
An aspect ratio describes the proportional relationship between width and height,
such as 16:9 for widescreen video or 4:3 for classic displays. This tool
reduces any width and height to its simplest ratio using the greatest common divisor.
Simplify or solve
In simplify mode, enter a width and height to get the ratio. In solve mode, enter a target ratio and one known side, and the calculator works out the missing dimension — ideal for resizing images and video without distortion.
How to use the Aspect Ratio Calculator
- Pick a mode. Choose simplify (width and height) or solve (ratio and one side).
- Enter your values. Type the dimensions or the ratio and known side.
- Read the result. See the simplified ratio or the missing dimension.
- Apply it. Use the ratio or size to resize media cleanly.
Frequently asked questions
How is the ratio simplified?
The calculator divides both width and height by their greatest common divisor, so 1920 × 1080 reduces to 16:9.
What does solve mode do?
Given a ratio and one dimension, it calculates the other dimension so the proportions are preserved exactly.
Can I use non-integer ratios?
Yes. Solve mode accepts decimal ratio values, and results are shown rounded to two decimal places where needed.
Is my data stored?
No. All calculations run in your browser and nothing is sent to a server.