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  1. Home
  2. Math Calculators
  3. Ratio Calculator

Ratio Calculator

Simplify ratios, solve proportions, scale ratios, and compare equivalent ratios. Calculate ratio to fraction, decimal, and percentage with step-by-step solutions.

Formula:a : b

Ratio Results

Simplified Ratio

2 : 3

Decimal0.6667
Percentage66.6667%
Fraction2/3

Calculator Mode

Enter Ratio

:

Results

Original

12 : 18

Simplified

2 : 3

Decimal

0.6667

Percentage

66.6667%

Fraction

2/3

Parts Total

5

Common Ratios

Golden Ratio

1:1.618

Design, Art

Screen 16:9

16:9

HD Video

Screen 4:3

4:3

Classic TV

Photo 3:2

3:2

35mm Film

Square

1:1

Instagram

1/3 Rule

1:2

Design

Cement:Sand

1:3

Mortar

Coffee:Water

1:15

Pour Over

Common Ratio Calculations

Quick-start with common scenarios

Practice Ratio Problems

Test your skills with practice problems

Practice with 5 problems to test your understanding.

Ratio Results

Simplified Ratio

2 : 3

Decimal0.6667
Percentage66.6667%
Fraction2/3

?How Do You Calculate Ratios?

A ratio compares two or more quantities. To simplify a ratio, divide all parts by their GCF. For example, 12:8 simplifies to 3:2 (divide by 4). To solve a proportion (a:b = c:x), use cross-multiplication: a*x = b*c, so x = (b*c)/a. Equivalent ratios have the same relationship (2:3 = 4:6 = 6:9).

What is a Ratio?

A ratio is a comparison between two or more numbers that shows their relative sizes. Written as a:b or a/b, ratios express the relationship between quantities without specifying actual values. Ratios are used in cooking, construction, finance, map scales, aspect ratios, and anywhere relative proportions matter.

Key Facts About Ratios

  • A ratio compares two or more quantities (parts to parts or part to whole)
  • Simplify by dividing all parts by their GCF: 12:8 = 3:2
  • Equivalent ratios: multiply or divide all parts by the same number
  • Proportion: two equal ratios (a:b = c:d). Cross multiply: ad = bc
  • Ratio to fraction: a:b means a/(a+b) of whole is first part
  • Common ratios: 1:1 (equal), 2:1 (double), 1.618:1 (golden ratio)
  • Scale ratio: multiply all parts by scale factor
  • Ratios can have more than two parts: 1:2:3 means parts in that proportion

Quick Answer

A ratio compares two or more quantities. To simplify a ratio, divide all parts by their GCF. For example, 12:8 simplifies to 3:2 (divide by 4). To solve a proportion (a:b = c:x), use cross-multiplication: a*x = b*c, so x = (b*c)/a. Equivalent ratios have the same relationship (2:3 = 4:6 = 6:9).

Frequently Asked Questions

A ratio compares two or more quantities. It shows the relative size of two values. For example, a ratio of 2:3 means for every 2 units of the first quantity, there are 3 units of the second. Ratios can be written as 2:3, 2/3, or "2 to 3".

A comparison of two quantities. 2:3 means for every 2 of the first, there are 3 of the second.

To simplify a ratio, divide both numbers by their greatest common factor (GCF). For example, 12:18 has a GCF of 6, so dividing both by 6 gives 2:3. The simplified ratio has the same relationship but uses smaller numbers.

Divide both numbers by their GCF. Example: 12:18 ÷ 6 = 2:3.

A proportion is an equation stating that two ratios are equal. For example, 1:2 = 3:6 is a proportion. Cross multiplication can be used to verify: if a:b = c:d, then a×d = b×c. Proportions are used to solve for unknown values.

An equation showing two equal ratios. 1:2 = 3:6. Verify with cross multiplication: a×d = b×c.

Use cross multiplication. For a:b = c:x, cross multiply to get a×x = b×c, then solve for x = (b×c)/a. For a:b = x:d, you get b×x = a×d, so x = (a×d)/b.

Cross multiply. For a:b = c:x, x = (b×c)/a. For a:b = x:d, x = (a×d)/b.

Equivalent ratios have the same value when simplified or converted to decimals. Examples: 1:2, 2:4, 3:6, and 50:100 are all equivalent (they all equal 0.5). Multiply or divide both parts by the same number to find equivalent ratios.

Ratios with the same value. 1:2 = 2:4 = 3:6 = 50:100 (all equal 0.5).

Ratios appear everywhere: recipes (2:1 flour to sugar), maps (1:50000 scale), finance (P/E ratio), mixing (3:1 paint dilution), aspect ratios (16:9 screens), and probability (1:6 odds). They're essential for scaling, comparing, and proportioning.

Recipes, maps, finance, paint mixing, screen aspect ratios, probabilities, and any scaling task.

Last updated: 2025-01-15

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Ratio Results

Simplified Ratio

2 : 3

Decimal0.6667
Percentage66.6667%
Fraction2/3