Percentage calculator
Calculate percentages, discounts and percentage changes, or recover an original value.
Calculations run in your browser. Inputs are not automatically saved.
How it works
Percentage change uses (B − A) ÷ |A| × 100. Original-value recovery uses final value ÷ (1 + rate ÷ 100). Enter −20 for a 20% decrease. Results use standard browser number arithmetic, rounded for display; they are not accounting-grade decimal calculations.
Text or numbers are not included in tool URLs.