Price Elasticity of Supply Calculator
From changes in price and quantity supplied, compute the price elasticity of supply (PES), how sensitive supply is to price.
Input Data
Results
At a glance:Price elasticity of supply = % change in quantity supplied ÷ % change in price, using the midpoint method. PES is typically positive; above 1 is elastic supply, below 1 inelastic. The midpoint % change = (new − old) ÷ ((old + new) ÷ 2).
Formula
%Δ quantity supplied = (final − initial) ÷ ((initial + final) ÷ 2).
%Δ price = (final − initial) ÷ ((initial + final) ÷ 2).
PES = %Δ quantity supplied ÷ %Δ price.
$$PES = \dfrac{\%\Delta Q_s}{\%\Delta P}$$$$\%\Delta Q_s = \dfrac{Q_1 - Q_0}{Q_0}, \; \%\Delta P = \dfrac{P_1 - P_0}{P_0}$$How to Use
- Enter the initial and final price.
- Enter the initial and final quantity supplied.
- Read the price elasticity of supply.
FAQ
What is price elasticity of supply and how is it calculated?
Price elasticity of supply (PES) measures how much the quantity supplied responds to a price change — the producer's sensitivity. The formula: PES = % change in quantity supplied ÷ % change in price. Because the law of supply says price up, quantity supplied up, price and quantity move together, so PES is usually positive (unlike demand elasticity, which is usually negative). This calculator uses the two-point method with the initial value as the base, simple and suitable for teaching and quick estimates.
What do the values of PES mean — elastic vs inelastic?
PES > 1 is elastic supply: quantity responds more than price (e.g. goods with idle capacity, short production cycles). PES < 1 is inelastic: quantity responds less than price (e.g. crops, scarce minerals, fixed-supply art). PES = 1 is unit elastic; PES = 0 is perfectly inelastic (fixed supply, vertical curve); PES → ∞ is perfectly elastic (horizontal curve). It tells how fast and how much the market can add supply when price rises.
What factors affect supply elasticity, and why is time so important?
It depends on how easily producers can adjust output: (1) spare capacity — idle capacity means quick expansion; (2) inventory — storable goods can flex via stock; (3) input availability — easy access to materials/labour means higher elasticity; (4) time — the most critical. In the very short run, output is nearly fixed (near inelastic); in the short run, overtime and more inputs help (more elastic); in the long run, new plants and new entrants appear (most elastic). That is why prices often spike when demand suddenly rises but stabilise later as supply catches up.
How is PES different from price elasticity of demand (PED) — why one positive, one negative?
Both measure sensitivity to price, but they measure opposite sides. PED measures the BUYER (consumer): price up, quantity demanded down → usually negative. PES measures the SELLER (producer): price up, quantity supplied up → usually positive. Magnitude interpretation is the same (|·| > 1 elastic, < 1 inelastic), but PED large means consumers are price-sensitive, PES large means producers can quickly adjust output. Time matters for both — both tend to be more elastic over longer periods. Together they describe how a market's two sides respond to price, which is the core of analysing price swings, tax incidence and equilibrium.
What is the practical meaning of supply elasticity, and who bears a tax?
Supply elasticity matters for business, price volatility and tax policy. For business: elastic supply (spare capacity, stock, short cycle) lets you seize a price rally by expanding output; inelastic supply (full capacity, long cycle) means watching orders slip away. For volatility: inelastic-supply markets (short-run crops, housing, scarce resources) swing violently in price, while elastic-supply goods are steadier. For tax incidence — the classic application: who bears a tax depends on the RELATIVE elasticities of supply and demand. The rule: the LESS elastic (more inelastic) side bears MORE of the tax, because it cannot easily avoid it. If supply is inelastic but demand elastic, producers cannot pass the tax on (consumers leave) and absorb more; if demand is inelastic but supply elastic, the tax is mostly shifted to consumers. So assess a tax's real effect by looking at both sides' elasticities — pair this tool with the demand-elasticity calculator.
Related Tools
References
Content review: Calculatorism Finance Team. Results are for reference only; please refer to the relevant authorities for the official figures.