Free online percentage calculator. Calculate percentages, percentage increase, decrease, difference, and reverse percentages instantly. Pure client-side, no ads.
This percentage calculator handles all common percentage calculations in one place. Whether you need to calculate a tip, figure out a discount, compute a percentage change, or find what percentage one number is of another — everything is instant and private. All calculations happen in your browser with no data sent to any server.
To calculate what X% of Y is, multiply Y by X and divide by 100. For example, 20% of 150 = 150 × 20 ÷ 100 = 30. Our calculator does this instantly — just enter the percentage and the value.
Percentage increase = ((New Value - Original Value) ÷ Original Value) × 100. For example, if a price goes from $100 to $130, the increase is ((130 - 100) ÷ 100) × 100 = 30%.
Percentage decrease = ((Original Value - New Value) ÷ Original Value) × 100. For example, if a price drops from $200 to $160, the decrease is ((200 - 160) ÷ 200) × 100 = 20%.
Percentage change (increase/decrease) assumes one value came before the other and shows direction. Percentage difference treats both values equally and shows how far apart they are relative to their average, regardless of which came first.