Ratio Calculator
Simplify ratios to their lowest terms and solve proportions with cross-multiplication. Step-by-step explanations.
About Ratio Calculator
This free ratio calculator handles two essential operations: simplifying ratios to their lowest terms and solving proportions with cross-multiplication. For simplification, it finds the GCD (greatest common divisor) and divides both terms to give you the simplest form. For proportion solving, it detects which value is missing and applies the cross-multiplication rule: a × d = b × c. Step-by-step explanations make it an excellent learning tool for students, teachers, and professionals working with ratios and proportions.
Ratio Simplification
Reduce any ratio to its simplest form using the greatest common divisor. See the GCD used and the result as a fraction and decimal.
Proportion Solver
Solve for any missing term in a proportion with three known values. Auto-detects which field is unknown and calculates it.
Cross-Multiplication
See the step-by-step cross-multiplication process: a × d = b × c. Great for learning and verifying your own work.
Multiple Representations
View ratios as simplified ratios, fractions, and decimals for a complete understanding of the relationship between values.
📋 Common Use Cases
Shopping & Discounts
Calculate sale prices, percentage discounts, and tip amounts instantly. Know exactly what you will pay before reaching the register.
Cooking & Recipe Scaling
Adjust recipe ingredient quantities using ratios and proportions. Scale recipes up for parties or down for smaller meals with perfect accuracy.
Academic Homework Help
Students can check their work and understand step-by-step solutions for fractions, percentages, and ratio problems across math and science courses.
Quick Business Math
Calculate markups, discounts, and proportional adjustments. Make fast, accurate pricing decisions without reaching for a physical calculator.
🪜 How to Use This Tool
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Enter your numbers
Type the values you want to calculate. Most calculators accept whole numbers, decimals, and fractions in standard notation. -
Select the operation or mode
Choose what you want to compute — percentage of a number, fraction arithmetic, or ratio simplification — depending on the calculator. -
See the result with explanation
The answer appears instantly. Most math calculators show step-by-step work so you understand how the result was derived. -
Copy or reuse the result
Click to copy the answer for use in homework, shopping decisions, or business calculations.