How to Use the Percentage Calculator
Our percentage calculator helps you solve common percentage problems quickly and accurately. Whether you need to find what percentage one number is of another, calculate percent change, or work backwards from a percentage result, this tool has you covered.
Calculate X% of Y
This is the most common percentage calculation. Enter the percentage and the number, and the calculator instantly shows you the result. For example, if you want to find 15% of 80, enter 15 as the percentage and 80 as the number to get 12.
Formula: Result = (Percentage × Number) ÷ 100
Percentage Change
Use percentage change to see how much a value has increased or decreased. This is commonly used for comparing prices, analyzing growth, tracking investments, or measuring any change over time.
Formula: Percent Change = ((New Value - Old Value) ÷ Old Value) × 100
For example, if a stock price goes from $50 to $65, the percentage change is ((65 - 50) ÷ 50) × 100 = 30% increase.
What Percent Is X of Y?
This calculation tells you what percentage one number represents of another. Enter the part (the smaller number) and the whole (the total), and the calculator shows you the percentage.
Formula: Percentage = (Part ÷ Whole) × 100
Reverse Percentage
Sometimes you know the result and the percentage, but need to find the original number. Reverse percentage calculation solves this problem. For example, if a 25% discount saved you $50, the original price was (50 × 100) ÷ 25 = $200.
Practical Examples
- Shopping: Calculate final prices after discounts or figure out how much you're saving
- Grades: Determine what percentage score you achieved on a test
- Finance: Calculate interest rates, investment returns, or budget percentages
- Business: Analyze profit margins, growth rates, or market share
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." When we say 50%, we mean 50 out of 100, or half.
Percentages are everywhere in daily life—from sales tax and tips to interest rates and statistics. Understanding how to calculate percentages helps you make better financial decisions, interpret data, and solve everyday problems.