Percentage Calculator

Calculate percentages, percentage change, and more — instantly

Instant results | Free to use

What is X% of Y?

What is % of =

X is what percent of Y?

is what % of =

Percentage Change

From to =

Percentage Difference

Between and =

Increase / Decrease by Percentage

% =

Quick Formulas

  • X% of Y

    (Y × X) / 100

  • X is what % of Y

    (X / Y) × 100

  • % Change

    ((New - Old) / Old) × 100

  • % Difference

    (|A - B| / ((A + B) / 2)) × 100

Common Conversions

  • 1/2 50%
  • 1/3 33.33%
  • 1/4 25%
  • 1/5 20%
  • 1/8 12.5%
  • 1/10 10%
  • 3/4 75%

Quick Tip

To find 10% of any number, simply move the decimal point one place to the left. For example, 10% of 250 = 25. Double that for 20%, halve it for 5%.

What Is a Percentage?

Understanding the mathematical concept behind percentage calculations

A percentage (from Latin per centum, meaning "by the hundred") is a way of expressing a number as a fraction of 100. It is denoted by the symbol %. For example, 45% means 45 out of 100, or 45/100, which equals 0.45 as a decimal.

Percentages are used universally in everyday life: from sales tax and tip calculations, to interest rates and exam scores, to statistics and data analysis. They provide a standardized way to compare proportions regardless of the original quantities involved.

Shopping & Finance

Discounts, sales tax, tips, interest rates, investment returns, and loan calculations all rely on percentages. Understanding them helps you make better financial decisions.

Education & Testing

Exam scores, GPA calculations, grade weightings, and academic performance metrics are all expressed as percentages for easy comparison across different scales.

Data & Statistics

Market share, population growth, survey results, and scientific measurements use percentages to normalize data and make comparisons meaningful regardless of scale.

How to Calculate Percentages: Step-by-Step Guide

Master the essential percentage formulas used in everyday calculations

1. Finding a Percentage of a Number

Result = (Number × Percentage) ÷ 100

Example: What is 20% of 150?

Result = (150 × 20) ÷ 100 = 30

2. Finding What Percentage One Number Is of Another

Percentage = (Part ÷ Whole) × 100

Example: 30 is what percent of 150?

Percentage = (30 ÷ 150) × 100 = 20%

3. Calculating Percentage Change (Increase or Decrease)

% Change = ((New Value - Old Value) ÷ Old Value) × 100

Example: Price went from $80 to $100.

% Change = ((100 - 80) ÷ 80) × 100 = 25% increase

4. Calculating Percentage Difference Between Two Values

% Difference = (|Value1 - Value2| ÷ ((Value1 + Value2) ÷ 2)) × 100

Example: Difference between 100 and 150.

% Difference = (50 ÷ 125) × 100 = 40%

Percentage, Decimal & Fraction Conversion Table

Quick reference for converting between percentages, decimals, and fractions

Percentage Decimal Fraction
1% 0.01 1/100
5% 0.05 1/20
10% 0.10 1/10
12.5% 0.125 1/8
20% 0.20 1/5
25% 0.25 1/4
33.33% 0.3333 1/3
50% 0.50 1/2
66.67% 0.6667 2/3
75% 0.75 3/4
100% 1.00 1/1
150% 1.50 3/2

Real-World Percentage Applications

How percentages are used in everyday calculations

Sales Tax Calculation

If an item costs $85 and sales tax is 8.25%:

Tax = $85 × 0.0825 = $7.01

Total = $85 + $7.01 = $92.01

Tip Calculation

For a $65 meal with a 18% tip:

Tip = $65 × 0.18 = $11.70

Total = $65 + $11.70 = $76.70

Investment Return

You invested $5,000 and it grew to $5,750:

Return = ((5750 - 5000) ÷ 5000) × 100 = 15%

Exam Score

You answered 42 out of 50 questions correctly:

Score = (42 ÷ 50) × 100 = 84%

Frequently Asked Questions

Common questions about percentages and how to calculate them

To find a percentage of a number, multiply the number by the percentage and divide by 100. For example, to find 25% of 200: (200 × 25) ÷ 100 = 50. Alternatively, convert the percentage to a decimal (25% = 0.25) and multiply: 200 × 0.25 = 50.
Percentage change measures how much a value has changed relative to its original value: ((New - Old) / Old) × 100. It has a direction (increase or decrease). Percentage difference measures the difference between two values relative to their average: (|A - B| / ((A + B) / 2)) × 100. It's used when neither value is clearly the "starting" value.
To convert a percentage to a decimal, divide by 100 or simply move the decimal point two places to the left. For example: 75% = 75 ÷ 100 = 0.75. To convert back, multiply by 100: 0.75 × 100 = 75%.
Use the formula: Percentage Increase = ((New Value - Original Value) ÷ Original Value) × 100. For example, if a stock price went from $40 to $52: ((52 - 40) ÷ 40) × 100 = 30% increase.
Divide the part by the whole and multiply by 100. For example, "15 is what percent of 60?" Answer: (15 ÷ 60) × 100 = 25%. This tells you that 15 represents 25% of 60.
Yes. A percentage greater than 100% simply means the value exceeds the reference amount. For example, if you scored 110 out of 100 possible points (with bonus), that's 110%. If a company's revenue grew from $1M to $3M, that's a 200% increase.
Use the same percentage change formula. If the result is negative, it's a decrease. For example, if a price dropped from $80 to $60: ((60 - 80) ÷ 80) × 100 = -25%. The price decreased by 25%.
If you know the result after adding a percentage, divide by (1 + percentage/100). For example, if a price after 20% tax is $120: Original = $120 ÷ 1.20 = $100. For a discount, divide by (1 - percentage/100).