Ratio Calculator – Simplify Ratios, Solve Proportions & Scale

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Whether you're comparing quantities, adjusting a recipe, or solving geometry homework, our 3-in-1 Ratio Calculator helps you simplify ratios to their lowest terms and solve for missing proportions instantly.

Modes Explained

  • Simplify Ratio: Reduces a ratio (like 12:8) to its simplest mathematical form (3:2) by finding the Greatest Common Divisor (GCD).
  • Solve Proportion (Equivalent Ratios): Solves the equation A : B = C : X. Just leave the element you want to find unknown, and we'll calculate it using cross-multiplication.
  • Scale Ratio: Enlarges or shrinks a ratio uniformly by a specific multiplier factor.

Proportion Formula

If A : B = C : X Then A / B = C / X Therefore, X = (B × C) / A

Frequently Asked Questions

To simplify a ratio, you find the Greatest Common Divisor (GCD) of both numbers, and divide both numbers by that GCD. For example, for 20:15, the GCD is 5. Dividing both by 5 gives 4:3.

A proportion is an equation or statement that says two ratios are equivalent. For instance, 1:2 = 2:4.

If a recipe calls for 2 cups of sugar to 3 cups of flour (2:3) and you want to double the recipe, you multiply both sides by your scale factor (2). The new ratio is 4:6.

Ratios and fractions both represent relationships between numbers. A fraction usually represents a "part to whole" relationship (1 slice of an 8 slice pizza), while a ratio can represent "part to part" (2 cups of water to 1 cup of rice).

Use cross-multiplication. If you have 3:4 = 6:X, multiply 4 by 6 (24), then divide by 3 to get X (which is 8).