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Percentage Calculator

Use this free Percentage Calculator to calculate percentages quickly and accurately. Find a percentage of a number, determine what percentage one number is of another, calculate percentage increase or decrease, and work out discounts and percentage changes.

Enter your numbers below and select the calculation you need. The calculator provides the result instantly and the formulas below explain how each percentage calculation works.

Online Percentage Calculator

1. What is X% of Y?

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2. What Percentage Is X of Y?

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3. Percentage Increase or Decrease

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4. Percentage Discount Calculator

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5. Find the Original Value

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What Is a Percentage?

A percentage is a way of expressing a number as a fraction of 100. The word "percent" means "per hundred." The percentage symbol is %.

For example, 25% means 25 out of 100, which is equivalent to 0.25 as a decimal or 1/4 as a fraction.

Percentage = (Part ÷ Whole) × 100

Percentages are widely used in finance, shopping, business, statistics, education, taxes, discounts, interest rates, test scores, data analysis and everyday calculations.

Percentage Formulas

Calculate a Percentage of a Number

Result = (Percentage ÷ 100) × Number

Example: What is 20% of 150?

20% of 150 = (20 ÷ 100) × 150
= 30

Find What Percentage One Number Is of Another

Percentage = (Part ÷ Whole) × 100

Example: What percentage is 30 of 120?

(30 ÷ 120) × 100 = 25%

Percentage Increase

Percentage Increase = ((New Value − Original Value) ÷ Original Value) × 100

Example: A price increases from 100 to 125.

((125 − 100) ÷ 100) × 100 = 25% increase

Percentage Decrease

Percentage Decrease = ((Original Value − New Value) ÷ Original Value) × 100

Example: A price decreases from 200 to 170.

((200 − 170) ÷ 200) × 100 = 15% decrease

Percentage Difference

When neither value is treated as the original or reference value, percentage difference can be calculated using the average of the two values.

Percentage Difference = |A − B| ÷ ((A + B) ÷ 2) × 100

Common Percentage Values

Percentage Decimal Fraction
1% 0.01 1/100
5% 0.05 1/20
10% 0.10 1/10
20% 0.20 1/5
25% 0.25 1/4
33.33% ≈ 0.3333 ≈ 1/3
50% 0.50 1/2
75% 0.75 3/4
100% 1 1
200% 2 2

Percentage Calculation Examples

Example 1: Calculate 15% of 240

Convert 15% to a decimal and multiply by 240:

0.15 × 240 = 36

Example 2: What percentage is 45 of 180?

(45 ÷ 180) × 100 = 25%

Example 3: Calculate a 20% increase from 500

500 × 1.20 = 600

Example 4: Calculate a 20% decrease from 500

500 × 0.80 = 400

Example 5: Calculate a 25% discount on $80

Discount = 80 × 0.25 = $20
Sale Price = 80 − 20 = $60

Where Are Percentages Used?

Percentages are used in many areas of everyday life and professional work, including:

  • Shopping discounts and sale prices
  • Taxes and tax rates
  • Tips and restaurant bills
  • Interest rates and financial calculations
  • Business profit and loss
  • Salary increases and reductions
  • Exam scores and grades
  • Statistics and data analysis
  • Population and growth calculations
  • Investment returns
  • Price increases and inflation calculations
  • Commission and sales calculations

Percentage Increase vs Percentage Points

Percentage change and percentage points are not the same thing. A percentage-point change is the simple arithmetic difference between two percentages.

If an interest rate changes from 5% to 7%, the change is 2 percentage points.

The relative percentage increase is:

((7 − 5) ÷ 5) × 100 = 40%

Therefore, the rate increased by 2 percentage points, which is a 40% relative increase.

Percentage, Decimal and Fraction Conversion

Percentage to Decimal

Divide the percentage by 100.

25% ÷ 100 = 0.25

Decimal to Percentage

Multiply the decimal by 100.

0.25 × 100 = 25%

Percentage to Fraction

Write the percentage as a fraction over 100 and simplify when possible.

25% = 25/100 = 1/4

For more advanced calculations, you can also use our Fraction Calculator.

Related Calculators

Discount Calculator Calculate discounts and final sale prices. Profit Margin Calculator Calculate profit margins and business percentages. Simple Interest Calculator Calculate simple interest and total amounts. Compound Interest Calculator Calculate compound interest and growth. Average Calculator Calculate averages from a set of numbers. Fraction Calculator Add, subtract, multiply and divide fractions.

Percentage Calculator FAQs

How do I calculate a percentage?
Divide the part by the whole and multiply by 100. The formula is Percentage = (Part ÷ Whole) × 100.
What is 20% of 100?
20% of 100 is 20 because 100 × 20 ÷ 100 = 20.
How do I calculate percentage increase?
Percentage increase is calculated as ((New Value − Original Value) ÷ Original Value) × 100.
How do I calculate percentage decrease?
Percentage decrease is calculated as ((Original Value − New Value) ÷ Original Value) × 100.
What percentage is one number of another?
Divide the first number by the second number and multiply by 100. For example, 25 is 25% of 100.
What is the difference between percentage change and percentage points?
Percentage change describes a relative change compared with the original value, while percentage points describe the arithmetic difference between two percentages.
How do I calculate a discount percentage?
Subtract the sale price from the original price, divide the result by the original price and multiply by 100.
How do I convert a decimal to a percentage?
Multiply the decimal by 100 and add the percent symbol. For example, 0.25 equals 25%.
How do I convert a percentage to a decimal?
Divide the percentage by 100. For example, 25% equals 0.25.
Can I use the percentage calculator for discounts?
Yes. You can calculate a discount amount and the final price by entering the original price and discount percentage.