Rule of Three Calculator
Enter three values and instantly solve for the fourth using direct or inverse proportion, with a clear calculation path.
No upload
Calculate a proportion
Both quantities change by the same ratio.
Labels
Values in the same column must already use the same unit. These fields do not convert units.
Quantity 1Quantity 2
Relation 1
corresponds to
Relation 2
corresponds to
Enter three valid values. The field marked as calculated is solved automatically.
Relation
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Scaling
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