Percentage Calculator
Calculate percentages, find proportions, or compute percentage change between two values.
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Understanding 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 one of the most fundamental mathematical concepts used in everyday life β from calculating sales tax and tips to understanding statistics, interest rates, and financial performance.
Three Types of Percentage Calculations
1. Finding a percentage of a number: This is the most common type β "What is 25% of 200?" The formula is simple: multiply the number by the percentage and divide by 100. In this example, (25 Γ 200) / 100 = 50. This calculation is useful for computing discounts, tax amounts, tips, and commission fees.
2. Finding what percentage one number is of another: This answers questions like "50 is what percent of 200?" The formula is: (part Γ· whole) Γ 100. So (50 / 200) Γ 100 = 25%. This is helpful when you want to express a portion of a total as a percentage, such as calculating your score on a test or your share of a group expense.
3. Percentage change between two values: This measures how much a value has increased or decreased relative to its original amount. The formula is: ((new value β old value) / |old value|) Γ 100. For example, if a stock price rose from $80 to $100, the percentage increase is ((100 β 80) / 80) Γ 100 = 25%. This calculation is essential for analyzing investment returns, price changes, salary adjustments, and business growth metrics.