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Ratio Calculator

Simplify ratios, solve proportions, calculate equivalent ratios, and split totals with this online ratio calculator.

Ratio calculator

:2:3

12:18 = 2:3

Calculation steps
  1. Step 1Find the greatest common factorGCF = 6
  2. Step 2Divide both terms12 ÷ 6 : 18 ÷ 6
  3. Step 3Write the simplified ratio2:3
Ratio Summary
Ratio
2:3
Equivalent form
2 to 3
Fraction form
2/3
Decimal
0.667
More Ratio Tools

Common Ratio Problems

Recipes

Keep ingredient quantities in the same proportion.

Flour : water = 2:1

Maps

Use a scale ratio to relate map distance to real distance.

Map scale = 1:1000

Business

Compare related figures such as sales and cost.

Sales : cost = 5:2

Display Ratios

Use 16:9 as a simple example of a ratio between dimensions.

Display ratio = 16:9

Formula

Simplify a ratio

Divide both terms by their greatest common factor

Solve a proportion

a:b = c:d → a × d = b × c

Examples

Simplify 12 to 18

12:18 = 2:3

Solve a missing proportion value

4:7 = x:21 → x = 12

Scale an equivalent ratio

3:5 scaled by 4 = 12:20

Split a total by a ratio

100 split by 3:2 = 60:40
Fraction CalculatorCalculate, simplify, add, subtract, multiply, divide, and convert fractions with this online fraction calculator.Percentage CalculatorCalculate percentages, percentage changes, and proportions.Average CalculatorCalculate averages, sums, counts, minimums, maximums, and ranges with this online average calculator.GCD CalculatorFind the GCD, GCF, or HCF of two or more integers and view each step of the Euclidean algorithm.Scientific CalculatorEvaluate arithmetic, powers, roots, trigonometry, and logarithms.

Frequently Asked Questions

How do I simplify a ratio?

Find the greatest common factor of both terms, then divide each term by that factor.

How do I solve a proportion with a missing value?

Cross multiply the known values, then divide to isolate the missing term.

What is an equivalent ratio?

Equivalent ratios compare quantities in the same proportion. Multiply or divide both terms by the same non-zero factor.

How do I split a total by a ratio?

Add the ratio terms, divide the total by that sum, and multiply the result by each ratio term.

Can a ratio contain decimals?

Yes. Decimal values are scaled to whole-number terms and then reduced to their simplest ratio.

Is the ratio 0:0 valid?

No. The ratio 0:0 is undefined because it has no unique simplified form.