Percentage Calculator
Percentages are one of the most fundamental concepts in everyday math, used in finance, shopping, taxes, science, and statistics. This calculator covers the five most common percentage operations: finding X% of a value, determining what percentage one number is of another, calculating percentage change between two values, increasing a value by a percentage, and decreasing a value by a percentage. Each result shows the formula so you understand exactly how the answer was reached.
Frequently Asked Questions
How do I calculate X% of Y?
Multiply Y by X/100. For example, 25% of 200 = 200 × 0.25 = 50. This is the most common percentage calculation used for tips, taxes, discounts, and commissions.
How do I find what percentage X is of Y?
Divide X by Y and multiply by 100. For example, 50 is what % of 200? → (50 / 200) × 100 = 25%. This is useful for calculating test scores, market share, or completion rates.
How is percentage change calculated?
Percentage change = ((New Value − Old Value) / Old Value) × 100. If sales went from 100 to 150: ((150 − 100) / 100) × 100 = +50%. A negative result indicates a decrease. This formula is used in finance, economics, and performance tracking.
What's the difference between percentage points and percent?
Percentage points measure the arithmetic difference between two percentages. If interest rates go from 3% to 5%, that is a 2 percentage point increase, but a 66.7% increase in relative terms. Always clarify which is meant in financial or statistical contexts.