Percentage Calculator
Calculate percentages — what is X% of Y, what % is X of Y, and percentage change.
How to use this tool
Why use this tool
FAQ
How do I calculate X% of Y?
How do I find percentage change?
What is the difference between percentage and percentage points?
How do I calculate a percentage increase?
How do I reverse a percentage to find the original?
About Percentage Calculator
Percentages appear in almost every area of daily life — discounts, tax rates, interest rates, grade scores, statistics, nutrition labels, and financial reports. This calculator handles all three common percentage problems in one place: finding a percentage of a number, finding what percentage one number is of another, and calculating the percentage change between two values.
The Three Percentage Formulas
What is X% of Y? Answer: Y × X ÷ 100. (What is 15% of 200? → 200 × 15 ÷ 100 = 30.) X is what percent of Y? Answer: X ÷ Y × 100. (30 is what % of 200? → 30 ÷ 200 × 100 = 15%.) Percentage change from X to Y: (Y − X) ÷ X × 100. (From 80 to 100 → (100 − 80) ÷ 80 × 100 = 25% increase.)
Percentage vs Percentage Points
One of the most common confusions in statistics and finance: a rate changing from 10% to 12% is an increase of 2 percentage points, but a 20% increase (since 2 is 20% of 10). Politicians and marketers exploit this ambiguity frequently. When you see a headline about a rate change, look for which measure is being used — they tell very different stories.
Common Real-World Uses
Use Mode 1 to calculate sale discounts (30% off $80), tips (18% of $65 bill), and tax amounts (8.5% VAT on $200). Use Mode 2 to find your exam score as a percentage (47 correct out of 60 questions = 78.3%), or to find a company's profit margin (net profit ÷ revenue × 100). Use Mode 3 to compare year-over-year revenue growth, stock price changes, or to check whether a "50% off sale" followed by "50% markup" actually returns to the original price (it doesn't — you lose 25%).