Percentage Calculator

Calculate percentages for all common scenarios. Find what percent one number is of another, calculate percentage increases and decreases (like salary raises or price markups), determine the original amount when you know the percentage, and solve percentage word problems. Works for grades, finances, statistics, tips, and everyday math.

Percentage Calculator

How the Calculation Works

Formula: Percentage = (Part / Whole) × 100

To calculate what percent one number is of another, divide the first number by the second, then multiply by 100. For example, 25 out of 100 is (25/100) × 100 = 25%.

To calculate a percentage of a number, multiply the number by the percentage decimal. For example, 20% of 500 = 500 × 0.20 = 100.

Worked Example

Example 1: What percent is 30 of 120?

  • Calculation: (30 / 120) × 100 = 25%

Example 2: What is 15% of 200?

  • Calculation: 200 × 0.15 = 30

Example 3: If you scored 85 out of 100 on a test, what's your percentage?

  • Calculation: (85 / 100) × 100 = 85%

How to Use This Calculator

Common Uses: Percentages appear in grades (85% on a test), discounts (20% off), tips (18% gratuity), taxes (sales tax percentage), interest rates, profit margins, and growth rates.

Percentage Change: To calculate percentage increase or decrease, use: ((New - Old) / Old) × 100. For example, if a price goes from $50 to $65, the increase is ((65-50)/50) × 100 = 30% increase.

Frequently Asked Questions

What is a percentage?

A percentage is a number expressed as a fraction of 100. 50% means 50 out of 100, or half. Percentages help compare numbers on a common scale (0-100%).

How do I calculate a percentage?

To find what percent A is of B: (A / B) × 100. To find a percentage of a number: Number × (Percentage / 100). Use this calculator to avoid math errors.

What's the difference between percentage and percentage points?

If a value goes from 30% to 35%, it increased by 5 percentage points. But the percentage change is ((35-30)/30) × 100 = 16.7% increase. They're different concepts.

How do I calculate percentage discount?

Multiply the original price by the discount percentage to find the discount amount. Then subtract from the original. For example, 20% off $50 = $50 - ($50 × 0.20) = $40.

How do I reverse calculate a percentage?

If 20% of a number equals 40, what's the number? Divide 40 by 0.20 to get 200. Work backward by dividing the result by the percentage decimal.