What are percentages?

Percentages are a way of expressing a proportion or fraction as part of a whole, where the whole is represented by 100. The term "percent" comes from the Latin language, where "per centum" means "for every hundred".

Percentages are written with the symbol %. For example, 30% means 30 out of 100.

Calculating percentages is used for several calculations:

• Comparing quantities.
• Expressing increases or decreases (e.g., "the price decreased by 20%)."
• Calculating interest, discounts, grades, etc.

Percentages are a very useful tool in mathematics, economics, statistics, and everyday life. For example, if you receive a 15% discount on a product that costs $100, you will pay $85.

How to calculate the percentage of a number?

To calculate a percentage of a number, you can use the following formula:

Percentage of a number = (Percentage / 100) × Number

For example, let's say you want to calculate 25% of 200:

• Convert the percentage to a decimal by dividing by 100: 25 ÷ 100 = 0.25
• Multiply the decimal by the number: 0.25 × 200 = 50
• So, 25% of 200 is 50.

Alternatively, you can use the formula: (Percentage × Number) / 100

Using the same example:

• Multiply the percentage by the number: 25 × 200 = 5000
• Divide the result by 100: 5000 ÷ 100 = 50

Both methods will give you the same result.

How to find a percentage of a number?

To find a percentage of a number, you can follow these steps:

1. Convert the percentage to a decimal by dividing by 100.
2. Multiply the decimal by the number.

The formula is:

Percentage of a number = (Percentage / 100) × Number

For example, let's say you want to find 20% of 200:

1. Convert 25% to a decimal: 20 ÷ 100 = 0.20
2. Multiply 0.25 by 200: 0.20 × 200 = 40

So, 20% of 200 is 40.

You can also use this formula in a calculator or a spreadsheet to quickly calculate percentages, if you don’t want to use the online percentage calculator provided.

Some other examples:

• 10% of 50 = (10 / 100) × 50 = 0.1 × 50 = 5
• 37% of 120 = (37 / 100) × 120 = 0.37 × 120 = 44.4
• 5% of 800 = (5 / 100) × 800 = 0.05 × 800 = 40

Remember, when working with percentages, it's often helpful to convert the percentage to a decimal first, and then multiply by the number.

Mathematical tricks to help you with percentages

Find below a set of handy mental math tricksthat you can actually use, when you need do calculate some percentages, and don't have a calculator at hand.

• 10% → just move decimal point one place left
  10% of 48 = 4.8
  
  
• 5% → half of 10%
  5% of 80 = 4
  
  
• 1% → move decimal point two places left
  1% of 650 = 6.5
  
  
• 20% → 10% × 2
  20% of 35 = 7
  
  
• 25% → divide by 4
  25% of 120 = 30
  
  
• 50% → divide by 2
  
  
• 75% → 50% + 25% (or just do × 0.75)

Examples of percentage calculations

Quick reference cheat sheet for percentages