Percentage Calculator
Calculate percentages quickly with multiple calculation modes. Find what percent one number is of another, calculate percentage changes, determine a percentage of any number, or apply percentage increases and decreases. Click any result to copy it to your clipboard.
How to Use This Percentage Calculator
This comprehensive percentage calculator provides five essential calculation modes to handle any percentage-related problem you might encounter. Each calculator section is designed for a specific type of calculation:
What is X% of Y? - Use this when you need to find a portion of a number. Enter the percentage and the total number. For example, to find 15% of 200, enter 15 in the first field and 200 in the second. This is perfect for calculating tips, discounts, tax amounts, and commission payments.
X is what % of Y? - This calculation determines what percentage one number represents of another. Enter the part in the first field and the whole in the second. If you scored 45 points out of 60, this tells you your percentage score. This is ideal for calculating test scores, completion rates, and proportions.
X is Y% of what? - Use this reverse calculation when you know a percentage and the resulting value but need to find the original number. If a 20% discount saved you $30, this calculator finds the original price. This is useful for working backwards from discounted prices or finding totals from partial information.
Percentage Change - Calculate how much something has increased or decreased as a percentage. Enter the starting value and ending value to see the percent change. This is essential for analyzing stock performance, price changes, population growth, and any before-and-after comparison.
Increase/Decrease by Percentage - Apply a percentage increase or decrease to any number. Enter the starting amount, select increase or decrease, and enter the percentage. This is perfect for calculating price markups, salary raises, depreciation, and price reductions.
Click any result to instantly copy it to your clipboard for use in other applications.
What is a Percentage?
A percentage is a mathematical way of expressing a number as a fraction of 100. The word itself comes from the Latin phrase "per centum," meaning "by the hundred" or "for every hundred." When you see 25%, it means 25 out of every 100, which equals 0.25 as a decimal or 1/4 as a fraction.
Percentages are one of the most practical mathematical concepts in everyday life. You encounter them constantly when shopping (discounts, sales tax, tips), managing finances (interest rates, investment returns, loan payments), analyzing data (survey results, statistics, probabilities), and measuring performance (test scores, completion rates, efficiency metrics).
The beauty of percentages lies in their ability to standardize comparisons. Whether comparing the growth of two companies with vastly different revenues or evaluating test scores across different point totals, percentages provide a common scale that makes meaningful comparison possible. A 10% increase means the same proportional change whether you are talking about $100 or $1,000,000.
Percentage Formulas and Examples
Finding a percent of a number: Result = (Percentage / 100) x Number
Example: 15% of 80 = (15 / 100) x 80 = 0.15 x 80 = 12
Finding what percent X is of Y: Percentage = (X / Y) x 100
Example: 24 is what percent of 80? = (24 / 80) x 100 = 30%
Calculating percentage change: Change = ((New - Old) / |Old|) x 100
Example: Price went from $50 to $65: ((65 - 50) / 50) x 100 = 30% increase
Applying a percentage increase: Result = Number x (1 + Percentage / 100)
Example: $200 increased by 25%: 200 x 1.25 = $250
Applying a percentage decrease: Result = Number x (1 - Percentage / 100)
Example: $200 decreased by 25%: 200 x 0.75 = $150