Ratio Calculator

Simplify a ratio or find the missing term in a proportion a:b = c:d.

All math runs in your browser — nothing is uploadedReviewed & updated: Methodology

Solve A:B = C:D — enter A, B, C and D is computed.

Ratio A : B
A = 342.9%
B = 457.1%
D (solves A:B = C:D)4.5
Simplified A : B3 : 4

How it works

Simplify by dividing both sides by GCD. Proportion: if a/b = c/d, then ad = bc.

Example

12:18 simplifies to 2:3. 2:3 = x:12 → x = 8.

Frequently asked questions

What is a ratio?
A comparison of two quantities by division.
Ratio vs fraction?
Same math; ratios express part-to-part, fractions part-to-whole.
How do I scale a recipe?
Multiply each ingredient by the same ratio.
Are 3:2 and 6:4 equal?
Yes — both simplify to 3:2.

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