Ratio & Proportion Calculator
Free ratio calculator. Solve proportions, simplify ratios, and find missing values in A:B = C:D. With step-by-step working.
Ratio & Proportion Solver
Leave one value empty to solve for it. Or fill all 4 to simplify the ratio.
Comprehensive Guide & Practice
Master the mathematical principles, formulas, and step-by-step methods with worked examples and FAQs.
1. What Is a Ratio?
A ratio is a comparison between two quantities using division. It tells you how many times one value contains or is contained in another. Ratios can be written as A:B, A/B, or "A to B".
2. Simplifying Ratios
Like fractions, ratios should be expressed in their simplest form. Divide both numbers by their Greatest Common Factor (GCF). Example: 12:8 → GCF = 4 → Simplified: 3:2.
3. Solving Proportions
A proportion is two equivalent ratios: A:B = C:D, or A/B = C/D. To solve for a missing value, use cross multiplication: A × D = B × C. If A=3, B=4, C=6, then D = (B×C)/A = (4×6)/3 = 8.
See also: Percentage Calculator | Fraction Calculator | Algebra Basics