Price Elasticity of Demand Calculator
Using the midpoint method on price and quantity changes, compute the price elasticity of demand, how sensitive demand is to price.
Input Data
Results
At a glance:Price elasticity of demand = % change in quantity ÷ % change in price, using the midpoint method so the result is the same in either direction. Midpoint % change = (new − old) ÷ ((old + new) ÷ 2). |Elasticity| > 1 is elastic, < 1 inelastic.
Formula
%Δ quantity = (final − initial) ÷ ((initial + final) ÷ 2).
%Δ price = (final − initial) ÷ ((initial + final) ÷ 2).
Elasticity = %Δ quantity ÷ %Δ price.
$$E_d = \\dfrac{\\Delta Q / \\bar{Q}}{\\Delta P / \\bar{P}}$$How to Use
- Enter the initial and final quantity.
- Enter the initial and final price.
- Read the price elasticity of demand.
FAQ
Is it normal for elasticity to be negative, and how do I read it?
Yes — the law of demand says price up, quantity down, so price elasticity of demand is usually negative. Read the absolute value: |Ed| > 1 is elastic (sensitive), |Ed| < 1 inelastic (insensitive), |Ed| = 1 unit elastic. At about −1.22 it is slightly elastic, meaning a price rise would slightly lower total revenue.
Why the midpoint method rather than a simple percentage?
Using the starting point as the denominator gives different elasticities for a price rise versus a fall, which is asymmetric. The midpoint method uses (change ÷ average of before and after), so the same interval gives the same elasticity either way — more robust and comparable. This is the arc-elasticity method used in textbooks and common tools.
What is the relationship between elasticity and total revenue?
When demand is elastic (|Ed| > 1), a price cut raises total revenue (volume grows more than price falls) and a rise lowers it. When inelastic (|Ed| < 1), a price rise raises total revenue (volume falls little), and a cut just thins revenue. At unit elasticity, price changes do not change total revenue. So knowing elasticity tells a seller whether to raise or cut price to grow revenue.
How should pricing differ for elastic versus inelastic goods?
This is the most practical use of elasticity — the direction of 'raise or cut price' is opposite. When demand is elastic (sensitive, e.g. generic snacks, substitutable daily goods), the strategy is 'thin margin, high volume' — cut price to win sales, avoid raising it. When demand is inelastic (necessities, no substitutes, small budget share, e.g. medicine, addictive goods, patented items), a moderate price rise raises revenue. More advanced: actively reduce your own product's elasticity through branding, differentiation and switching costs so you gain pricing power. Use this calculator to find your product's elasticity first, then decide direction, and check profit with a margin calculator rather than revenue alone.
What factors affect demand elasticity, and why is longer time more elastic?
Elasticity is shaped by: (1) number and closeness of substitutes — more substitutes means more elastic; (2) necessity vs luxury — necessities are inelastic; (3) budget share — small-share items are inelastic; (4) time — crucially, longer time means more elastic, because consumers can find substitutes, change habits and adjust lifestyle. A classic example is petrol: short-run, people still drive (inelastic); long-run, they buy fuel-efficient cars or move closer (more elastic). So do not assume a small short-run sales drop means you can keep raising price — the long-run reaction may erode sales. This tool computes arc elasticity for a specific interval and time; elasticity differs across horizons and contexts.
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References
Content review: Calculatorism Finance Team. Results are for reference only; please refer to the relevant authorities for the official figures.