Percentage Calculator
Calculate percentages quickly with three different modes.
What is X% of Y?
Result
50
Understanding Percentages
Percentages are one of the most widely used mathematical concepts in everyday life. From calculating sales tax and discounts to understanding statistics, investment returns, and grades, percentages provide a standardized way to express proportions and changes. The word "percent" literally means "per hundred," representing a fraction out of 100.
This percentage calculator offers three essential modes: finding a percentage of a number (e.g., "What is 25% of 200?"), determining what percentage one number is of another (e.g., "50 is what percent of 200?"), and calculating the percentage change between two values (e.g., "What is the percentage change from 80 to 100?"). These three operations cover the vast majority of percentage calculations you will encounter.
Understanding percentage change is particularly important in finance and business. When analyzing investment returns, sales growth, price changes, or economic indicators, percentage change provides a normalized way to compare values regardless of their absolute size. A $100 increase on a $1,000 investment (10%) is very different from a $100 increase on a $100,000 portfolio (0.1%).
Percentages also play a crucial role in data interpretation and media literacy. News reports frequently cite percentages when discussing economic trends, survey results, and scientific findings. Being comfortable with percentage calculations helps you critically evaluate claims and make better-informed decisions in both personal and professional contexts.
Common Use Cases
- Shopping: calculate sale prices, discounts, and how much you save
- Tipping: quickly compute restaurant tips at different percentage rates
- Finance: figure out investment returns, interest rates, and portfolio allocation
- School and work: compute grades, performance metrics, and statistics
- Cooking: scale recipes up or down by a given percentage
Quick Percentage Tips
- ✓To find 10% of any number, simply move the decimal point one place to the left
- ✓To find 5%, calculate 10% and divide by 2
- ✓To find 1%, move the decimal point two places to the left
- ✓For percentage change, remember: (New - Old) / |Old| x 100
- ✓A 50% increase followed by a 50% decrease does NOT return to the original value; it results in 75% of the original
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 (25 x 200) / 100 = 50. You can also convert the percentage to a decimal (25% = 0.25) and multiply: 0.25 x 200 = 50.
How do I find what percentage one number is of another?
Divide the part by the whole and multiply by 100. For example, to find what percentage 50 is of 200: (50 / 200) x 100 = 25%. This tells you that 50 is 25% of 200.
How do I calculate percentage change?
Subtract the old value from the new value, divide by the absolute value of the old value, and multiply by 100. For example, from 80 to 100: (100 - 80) / 80 x 100 = 25% increase. A negative result indicates a decrease.
What is the difference between percentage points and percent?
A percentage point is an absolute difference between two percentages. If an interest rate goes from 5% to 7%, that is a 2 percentage point increase, but a 40% relative increase. This distinction matters in finance and statistics.