Proportion Calculator

Last updated: April 5, 2026

Proportion: a / b = c / d. Enter three values; we solve the fourth.

Solve for

Result

4.50000000

Calculator by CalculatorNut

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How to Use

Enter three of four values depending on mode; the tool solves the fourth.

Formula

If a/b = c/d then ad = bc (cross multiply).

FAQ

Zero denominators?: Proportions with b=0 are invalid—enter nonzero b.
Ratios vs fractions?: Same math—keep units consistent across the equation.
Rounding?: Shown to several decimals; round per your context.

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