How to Calculate Percentages
A percentage represents a fraction of 100. Saying "25%" means 25 out of every 100, or 0.25 as a decimal. This calculator handles the four most common percentage calculations people need in everyday life, shopping, and finance.
Calculation Types Explained
What is X% of Y? Multiply Y by X/100. Example: 15% of 200 = 200 × 0.15 = 30. Useful for calculating tips, discounts, tax amounts, and investment returns.
X is what % of Y? Divide X by Y and multiply by 100. Example: 30 is what % of 200? 30 ÷ 200 × 100 = 15%. Useful for understanding proportions and ratios.
Percentage Change calculates the relative change between two values: ((New − Old) ÷ Old) × 100. Useful for comparing prices, salaries, stock performance, and economic data.
Increase/Decrease applies a percentage change to a starting value. Useful for calculating sale prices, salary raises, inflation adjustments, and tax additions.
Common Uses
- Shopping — calculate sale prices and discounts quickly.
- Tipping — figure out 15%, 18%, or 20% of a restaurant bill.
- Finance — work out interest amounts, investment returns, and tax rates.
- Work — calculate profit margins, pay raises, and budget allocations.
- School — convert between fractions, decimals, and percentages for homework and exams.