Percentage Calculations Explained
Percentages are used in countless everyday situations. Understanding how to calculate percentages is essential for financial planning, shopping, and data analysis.
1. What is X% of Y?
This calculation determines the value of a percentage of a number. The formula is:
Value = (Percentage ÷ 100) × NumberExample: What is 20% of 150? (20 ÷ 100) × 150 = 30.
2. X is What Percent of Y?
This finds what percentage one number is of another. The formula is:
Percentage = (Part ÷ Whole) × 100Example: 30 is what percent of 150? (30 ÷ 150) × 100 = 20%.
3. Percentage Change
This calculates the percentage increase or decrease from one value to another.
Change (%) = ((New Value - Old Value) ÷ Old Value) × 100If the result is positive, it's an increase. If negative, it's a decrease.
Example: A price increases from $100 to $120. The percentage change is ((120 - 100) ÷ 100) × 100 = 20% increase.
Real World Uses
Shopping & Discounts
Calculate sale prices, discounts, and savings on purchases.
Financial Planning
Track investment returns, interest rates, and financial growth.
Tips & Gratuities
Calculate appropriate tips at restaurants and for services.
Data Analysis
Compare statistics, analyze trends, and interpret survey results.