Price Elasticity of Demand (PED) is the ratio of the percentage change in demand to the percentage change in price. It tells us how much a price change will affect the quantity sold.
PED = (ΔQ ÷ Q) ÷ (ΔP ÷ P)
|PED| > 1 → elastic · |PED| < 1 → inelastic
Price increased 10%, demand fell 15%
PED = −15% ÷ 10% = −1.5 (elastic)
Calculate it yourself
Use the price elasticity calculator.