Free Percentage Calculator - All Percent Calculations

Calculate percentages, percentage changes, discounts, tips, and more. The most versatile percentage calculator for everyday math.

Calculate Percentage of a Number
Find what percentage of a number equals another number

Percentage Calculation Types

Find Percentage of a Number

Calculate what X% of Y equals. Example: 25% of 80 = 20

Formula: (Number × Percentage) ÷ 100

Percentage Change

Find increase or decrease between two values. Example: $80 to $100 = 25% increase

Formula: ((New - Old) ÷ Old) × 100

What Percent Is X of Y?

Determine the percentage relationship. Example: 30 is 25% of 120

Formula: (X ÷ Y) × 100

Common Use Cases

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Shopping

Calculate sale prices, discounts, and tax

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Finance

Interest rates, returns, profit margins

📚

Education

Grade calculations, test scores

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Statistics

Data analysis, survey results

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Tips

Restaurant tips, service gratuities

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Growth

Track changes over time

Quick Examples

Example 1: Sale Price
Item costs $80, 25% off discount
Sale price: $80 - ($80 × 0.25) = $60
Example 2: Tip Calculation
Bill is $45, want to leave 18% tip
Tip: $45 × 0.18 = $8.10
Example 3: Grade Percentage
Scored 42 out of 50 points
Grade: (42 ÷ 50) × 100 = 84%
Example 4: Price Increase
Rent went from $1,200 to $1,350
Increase: ((1350-1200) ÷ 1200) × 100 = 12.5%

Verified Calculator

Formula source: Standard mathematical percentage formulas

This calculator uses universally accepted mathematical formulas for all percentage operations.

Learn more about our verification process

💡 Percentage Mental Math Tips

  • 10%: Move decimal one place left ($80 → $8)
  • 5%: Find 10%, then halve it
  • 15%: Find 10% + 5%
  • 20%: Find 10% and double it
  • 25%: Divide by 4
  • 50%: Divide by 2

Frequently Asked Questions About Percentages

To find a percentage of a number, multiply the number by the percentage and divide by 100. Formula: Result = (Number × Percentage) ÷ 100. For example, to find 25% of 80: (80 × 25) ÷ 100 = 20. You can also convert the percentage to a decimal (25% = 0.25) and multiply: 80 × 0.25 = 20.

Percentage change measures the difference between two values as a percentage of the original. Formula: ((New Value - Old Value) ÷ Old Value) × 100. For example, if a price increased from $50 to $60: ((60 - 50) ÷ 50) × 100 = 20% increase. A negative result indicates a decrease.

To find what percentage A is of B, divide A by B and multiply by 100. Formula: (A ÷ B) × 100 = Percentage. For example, what percent is 30 of 120? (30 ÷ 120) × 100 = 25%. So 30 is 25% of 120.

To calculate a discount: 1) Convert the discount percentage to a decimal (e.g., 20% = 0.20); 2) Multiply the original price by this decimal to find the discount amount; 3) Subtract from the original price. Example: 20% off $80 = $80 - ($80 × 0.20) = $80 - $16 = $64. Or use: Original × (1 - discount%) = $80 × 0.80 = $64.

Percentage points measure the absolute difference between two percentages, while percent change measures relative change. If interest rates go from 5% to 7%, that's a 2 percentage point increase, but a 40% relative increase ((7-5)/5 × 100). This distinction is crucial in finance and statistics.

To add a percentage: multiply the value by (1 + percentage/100). Example: Add 15% to $200 = $200 × 1.15 = $230. To subtract: multiply by (1 - percentage/100). Example: Subtract 15% from $200 = $200 × 0.85 = $170. This method is commonly used for calculating taxes, tips, and discounts.

Understanding Percentage Calculations

Percentages are fundamental to everyday math, from calculating discounts while shopping to understanding interest rates on loans. Our free percentage calculator handles all types of percentage calculations with instant, accurate results.

The word "percent" comes from the Latin "per centum," meaning "by the hundred." A percentage is simply a way of expressing a number as a fraction of 100. This makes comparisons easy across different scales and is why percentages are used universally in finance, statistics, and everyday life.

Understanding the difference between percentage points and percent change is important. If interest rates go from 5% to 7%, that's a 2 percentage point increase, but a 40% relative increase. This distinction matters significantly in financial and statistical contexts.

Whether you're calculating sale prices, determining tips, analyzing data, or working on homework, our percentage calculator provides the tools you need. The calculator supports multiple percentage operations in one convenient interface.