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Ratio Calculator

The Ratio Calculator simplifies a ratio like 12:8 down to 3:2, and solves the missing term in a proportion such as 3:4 = 6:x. Useful for recipes, mixing, scaling and comparing proportions.

What this means

A ratio compares two quantities, like 3:4. Simplifying divides both parts by their greatest common factor. Solving a proportion finds the unknown term that keeps the two ratios equal.

How we calculate it

Formula

Simplify: A:B → (A ÷ g):(B ÷ g) where g = gcd(A, B). Solve: A/B = C/x → x = B × C ÷ A.

Worked example

Simplify 12:8 and solve 3:4 = 6:x:

  1. 1gcd(12, 8) = 4, so 12:8 = 3:2
  2. 2x = 4 × 6 ÷ 3 = 8

Important assumptions

  • Ratios are assumed to be positive for simplification.

Frequently asked questions

What is the simplest form of a ratio?

When the two numbers share no common factor greater than 1. For example, 3:2 cannot be reduced further.

How do I scale a recipe ratio?

Multiply both parts by the same number. If the recipe is 2:3 and you double it, it becomes 4:6.

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