Ratio Calculator
Simplify ratios, scale them up, and solve proportions.
Simplify & scale a ratio
:× scale
Simplified
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Scaled (×1)
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Solve a proportion: A : B = C : D
:=:
D
How it's calculated
- Simplify
- A : B = (A ÷ GCD) : (B ÷ GCD)
- Proportion
- A : B = C : ? → ? = B × C ÷ A
The greatest common divisor (GCD) is the largest number that divides both terms, so 12:18 becomes 2:3.
Proportions use cross-multiplication: if 2 cups of flour serve 3 people, 6 people need 2 × 6 ÷ 3 = 4 cups.
Frequently asked questions
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