How does the simplify mode work?

It finds the greatest common divisor (GCD) of the two integer-rounded numbers using the Euclidean algorithm, then divides both sides by it.

Yes. For simplify mode the values are rounded to the nearest integer before the GCD is computed, since ratios are conventionally whole numbers.

How is the missing side solved?

If A:B = X:Y and you know X, then Y = X·B/A. If you know Y, then X = Y·A/B.

The tool expects positive numbers for ratios. Negative inputs are rejected.

No — all math is local to your browser.

Solve the missing side of a ratio, or simplify it with GCD.

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Watch a quick simulation of this tool in action — no file needed.

Follow these steps — everything happens instantly in your browser.

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Step 1. Use the “Solve missing” tab: enter a ratio A:B, pick which side you know, and enter its value.
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Step 2. Or use the “Simplify ratio” tab: enter two numbers to reduce them to lowest terms.
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Step 3. Copy any result with the Copy button.

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