Percentage Calculator
Quickly calculate percentages and percentage variations online.
What is X % of Y?
X is what percentage of Y?
Percentage change from X to Y
How to Calculate Percentages
Percentages express a number as a fraction of 100. They're used everywhere — from discounts and tips to tax rates and exam scores. Our calculator handles all common percentage operations: finding a percentage of a number, calculating what percent one number is of another, and determining percentage change.
Three Common Calculations
What is X% of Y? Multiply Y by X/100. Example: 15% of 200 = 200 × 0.15 = 30.
X is what % of Y? Divide X by Y and multiply by 100. Example: 45 is what % of 180? → 45/180 × 100 = 25%.
Percentage change from X to Y: ((Y-X)/X) × 100. Example: Price went from 80 to 96 → (96-80)/80 × 100 = +20% increase.
Practical Examples
Example 1 — Sale discount: A €120 item at 30% off: discount = 120 × 0.30 = €36. You pay €84.
Example 2 — Tip calculation: 18% tip on a $67 bill: 67 × 0.18 = $12.06. Total: $79.06.
Example 3 — Grade calculation: 42 correct out of 50 questions: (42/50) × 100 = 84%.
Example 4 — Reverse percentage: An item costs €75 after a 25% discount. Original price: 75 / (1 - 0.25) = 75 / 0.75 = €100.
Frequently Asked Questions
How do I calculate a percentage of a number?
Multiply the number by the percentage and divide by 100. For example, 25% of 200 is 200 × 25 / 100 = 50. Our calculator does this instantly.
How do I find what percentage one number is of another?
Divide the part by the whole and multiply by 100. For example, 30 out of 120 is (30/120) × 100 = 25%.
How do I calculate percentage increase or decrease?
Subtract the original from the new value, divide by the original, and multiply by 100. A change from 80 to 100 is a 25% increase.
Can I calculate reverse percentages?
Yes. If a discounted price is 80 and the discount was 20%, the original price is 80 / (1 - 0.20) = 100. Enter any two values to find the third.