Ratio Calculator
Free ratio calculator to simplify ratios and solve proportions — find missing values with cross-multiplication instantly.
Ratio Calculator
Ratio Calculator
Simplify ratios or find missing proportion values
Result
Smart Insights
Personalized takeaways from your numbers.
Real-Life Examples
Reduce to lowest terms
Find missing value
The Formula Behind It
a:b simplified by GCD; scale via cross-multiplicationVariables
- a:b simplified by GCD
- Cross-multiply for proportions
How It Works
- Choose simplify ratio or find missing proportion value.
- Enter the ratio or proportion values.
- View the simplified ratio or missing value instantly.
About Ratio Calculator
The Ratio Calculator simplifies ratios to their lowest terms and solves proportion problems using cross-multiplication. Use it for recipe adjustments, map scales, financial ratios, and any situation where proportional relationships matter.
Simplifying Ratios
Divide both parts of a ratio by their GCD. The ratio 12:8 becomes 3:2. Order matters — 3:2 is not the same as 2:3.
Proportions
If a:b = c:d, then a × d = b × c. Enter three known values to find the fourth. This is essential for scaling recipes, mixing solutions, and solving word problems. Related tools: Fraction Calculator for fractional quantities, Percentage Calculator for percent-based ratios, and Markup Calculator for cost-to-price ratios.
Related Tools You May Need
Continue your calculation with these free tools on Online Calculators.
Frequently Asked Questions
How do I simplify a ratio?
Divide both parts by their greatest common divisor. 12:8 simplifies to 3:2.
How do I find a missing value in a proportion?
Use cross-multiplication. If 3:5 = x:20, then x = (3 × 20) / 5 = 12.
What is the difference between ratio and proportion?
A ratio compares two quantities (3:2). A proportion states two ratios are equal (3:2 = 6:4).
Can ratios include decimals?
Yes, but it is often clearer to convert to whole numbers first by multiplying both parts by a power of 10.
How do I scale a ratio?
Multiply or divide both parts by the same factor. 2:3 scaled by 4 becomes 8:12.
Is order important in a ratio?
Yes. 3:5 is not the same as 5:3. Always match the order to your problem context.