Percentage Calculator
Calculate percentages instantly. Results update live as you type. Everything runs in your browser.
What is % of ?
30
is what % of ?
22.5%
Percentage change from to
+25%
Increase of 20
%
180
How to Calculate Percentages
A percentage is a number expressed as a fraction of 100. The word comes from Latin "per centum" meaning "by the hundred." Percentages are used everywhere: discounts, taxes, tips, grades, statistics, and financial returns.
Formulas
- X% of Y — Multiply: Y × (X / 100). Example: 15% of 200 = 200 × 0.15 = 30
- X is what % of Y — Divide: (X / Y) × 100. Example: 45 is what % of 200 = (45/200) × 100 = 22.5%
- Percentage change — ((New - Old) / Old) × 100. Example: 80 to 100 = ((100-80)/80) × 100 = +25%
- Increase by X% — Value × (1 + X/100). Example: 150 increased by 20% = 150 × 1.20 = 180
- Decrease by X% — Value × (1 - X/100). Example: 150 decreased by 20% = 150 × 0.80 = 120
Common Uses
- Shopping — Calculate sale prices, discounts, and tax amounts
- Finance — Interest rates, investment returns, profit margins
- School — Test scores, GPA calculations, grade thresholds
- Business — Growth rates, market share, conversion rates
- Health — Body fat percentage, nutrient daily values