How to Calculate Percentages
Percentages are used everywhere—shopping discounts, tax calculations, statistics, and finance. This guide covers the most common percentage calculations.
Basic Percentage
To find X% of Y: multiply Y by X/100. Example: 25% of 200 = 200 × 0.25 = 50. This is the most common calculation—used for discounts, tips, and proportions.
Percentage Change
Percentage change = ((New − Old) / Old) × 100. A positive result means increase; negative means decrease. Example: price went from $80 to $100 = ((100−80)/80) × 100 = 25% increase.
Margin vs Markup
Margin = (Profit / Selling Price) × 100. Markup = (Profit / Cost) × 100. They use different denominators. A 50% markup is only a 33% margin. Our calculators handle both.