How to Calculate Percentages
A percentage is a way of expressing a number as a fraction of 100. The word "percent" comes from the Latin per centum, meaning "by the hundred." Percentages are used everywhere in daily life — from calculating tips and discounts to understanding statistics and financial data.
Finding X% of a Number
To find X% of a number Y, multiply Y by X and divide by 100. The formula is:
Result = (X / 100) × Y
Example: What is 25% of 200?
Result = (25 / 100) × 200 = 50
Finding What Percentage X Is of Y
To find what percentage one number is of another, divide the part by the whole and multiply by 100:
Percentage = (X / Y) × 100
Example: 50 is what percent of 200?
Percentage = (50 / 200) × 100 = 25%
Calculating Percentage Change
Percentage change measures how much a value has increased or decreased relative to its original value:
Change = ((New - Old) / |Old|) × 100
Example: From 100 to 150
Change = ((150 - 100) / 100) × 100 = +50%
A positive result indicates an increase, while a negative result indicates a decrease.
Common Percentage Calculations
- Tips: A 15% tip on a $50 meal = $7.50
- Discounts: 20% off a $80 item = $16 saved, you pay $64
- Tax: 8% sales tax on $100 = $8 in tax, total $108
- Grade: Scoring 45 out of 60 = 75%
Frequently Asked Questions
How do I calculate a percentage on a calculator?
Simply enter the percentage value, divide by 100, then multiply by the number. For example, to find 15% of 200: type 15 ÷ 100 × 200 = 30. Or use our free tool above for instant results.
What is the difference between percentage and percentile?
A percentage represents a portion of 100 (e.g., 85% on a test). A percentile indicates a rank relative to others (e.g., 90th percentile means you scored higher than 90% of participants).
Can a percentage be more than 100%?
Yes. A percentage greater than 100% means the value exceeds the reference amount. For example, if a stock price goes from $50 to $150, that is a 200% increase.