Updated
Using Price elasticity of demand calculator
Calculate demand elasticity using midpoint percentage changes in quantity and price.
Elasticity = [(Q₂ − Q₁)/average Q] ÷ [(P₂ − P₁)/average P]. The signed result is shown. Two observations do not establish a causal demand curve; other factors may have changed. Fixed assumptions only: no taxes, fees, changing returns, guarantees or product eligibility. Amounts share one currency. The same midpoint formula also measures supply elasticity when the quantities describe supply. The demand sign interpretation must not be applied to supply.
A worked example
Example inputs: initial price = 10, new price = 12, initial quantity demanded = 100, new quantity demanded = 80. Midpoint price elasticity = -1.22222222222.
Before you use the result
Elasticity = [(Q₂ − Q₁)/average Q] ÷ [(P₂ − P₁)/average P]. The signed result is shown. Two observations do not establish a causal demand curve; other factors may have changed. Fixed assumptions only: no taxes, fees, changing returns, guarantees or product eligibility. Amounts share one currency.
Example results for initial price
These examples use New price: 12; Initial quantity demanded: 100; New quantity demanded: 80. They are reference calculations, not recommended settings.
| Initial price | Midpoint price elasticity |
|---|---|
| 5 | -0.269841269841 |
| 10 | -1.22222222222 |
| 20 | 0.444444444444 |
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ToolOctopus. “Price elasticity of demand calculator.” Updated 2026-09-26. https://tooloctopus.com/price-elasticity-of-demand-calculator.
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