Percentage Calculator
Calculate percentages, percentage change, and ratios with three easy calculators.
About This Tool
The Percentage Calculator solves all common percentage problems: finding what percent one number is of another, calculating a percentage of a value, and determining percentage increase or decrease. It is a quick, everyday tool for shopping discounts, tip calculations, grade conversions, and financial analysis.
What is Y% of X?
X is what % of Y?
Percentage Change
How to Use
- Use the first calculator to find X% of a number (e.g., 25% of 200 = 50).
- Use the second calculator to find what percentage one number is of another (e.g., 50 is 25% of 200).
- Use the third calculator to find the percentage increase or decrease between two numbers.
- Results are calculated instantly when you click Calculate.
Frequently Asked Questions
How do I calculate a percentage?
To find X% of Y, multiply Y by X/100. For example, 15% of 200 = 200 x 0.15 = 30. To find what percentage X is of Y, divide X by Y and multiply by 100. For example, 30 is what % of 200? Answer: (30/200) x 100 = 15%.
How do I calculate percentage change?
Percentage change = ((New Value - Old Value) / |Old Value|) x 100. If the result is positive, it's an increase. If negative, it's a decrease. For example, from 80 to 100: ((100-80)/80) x 100 = 25% increase.
How do I calculate a discount percentage?
To find the discounted price: Original Price x (1 - Discount%/100). For example, 30% off $80 = $80 x 0.70 = $56. To find the discount percentage: ((Original - Sale Price) / Original) x 100.
What is the difference between percentage and percentage points?
A percentage is a relative measure, while percentage points measure the absolute difference between two percentages. If interest rates go from 3% to 5%, that's a 2 percentage point increase but a 66.7% increase in rate. This distinction matters in finance and statistics.
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How It Works
The calculator handles three fundamental percentage operations. First, "What is X% of Y?": Result = Y × (X / 100). For example, 15% of 200 = 200 × 0.15 = 30.
Second, "X is what % of Y?": Percentage = (X / Y) × 100. For example, 30 is what % of 200? → (30 / 200) × 100 = 15%.
Third, "Percentage change from X to Y": Change = [(Y − X) / |X|] × 100. A positive result indicates an increase, while a negative result indicates a decrease. For example, from 80 to 100: [(100 − 80) / 80] × 100 = 25% increase.
Additional calculations include reverse percentage (finding the original value before a percentage was applied) and compound percentage changes. All operations use standard floating-point arithmetic with results displayed to two decimal places by default.
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