Unit & Ratio Calculator

Solve A : B = C : ?, scale a ratio by N, and convert length, mass and volume units with exact standard factors.

How to use

Choose a mode at the top — proportion or unit conversion.
Proportion: fill in A, B and C, pick the value to solve, and the last one is filled in for you.
Add a scale factor (× N) to see the same ratio multiplied by N.
Unit conversion: pick a unit group, the from and to units and a value to get the result plus a full unit table.

How is the proportion solved?

In A : B = C : D the inner product equals the outer product (A×D = B×C), so the missing value follows from the other three.

Are the conversion factors exact?

Yes. They are the defined standard values, such as 1 inch = 25.4 mm and 1 pound = 453.59237 g.

Which volume units are used?

fl oz and gallon are US units. One US gallon is 3.785411784 L, and one cup is taken as 240 ml.

Which tonne is used?

The metric tonne of 1,000 kg.

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