Percentage Calculator

How to calculate a percentage

A percentage expresses a number as a fraction of 100. To find X% of a number Y, multiply Y by X and divide by 100 — for example, 20% of 150 is (20 × 150) / 100 = 30. This calculator handles the three most common percentage questions people search for: finding a percentage of a value, finding what percent one number is of another, and finding the percentage increase or decrease between two values.

Percentage change formula

Percentage change is calculated as ((New Value − Old Value) / Old Value) × 100. A positive result means an increase, while a negative result means a decrease. This is useful for tracking price changes, salary raises, weight loss, business growth, and exam score improvements.

Common uses

• Calculating discounts and sale prices while shopping
• Working out grade percentages from test scores
• Tracking growth or decline in business metrics
• Splitting commissions, taxes, or tips