What Is Price Elasticity of Demand?

Price Elasticity of Demand (PED) measures how sensitive consumers are to price changes — specifically, how much the quantity demanded changes when the price of a product changes by 1%. It is one of the most important concepts in economics, microeconomics, and business strategy, used to answer a critical question: if I raise prices, will I earn more or less money?

Use the Price Elasticity of Demand calculator above to compute PED using the midpoint method, predict quantity changes from price moves, model revenue impacts, and analyze cross-price elasticity between related goods.

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Pricing Strategy

Businesses use PED to set profit-maximizing prices. Raising price on an inelastic product (PED < 1) increases total revenue. Raising price on an elastic product (PED > 1) destroys revenue.

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Government Policy

Tax authorities model PED before imposing sin taxes on cigarettes (PED ≈ 0.4), alcohol (PED ≈ 0.5), and gasoline (PED ≈ 0.2) — inelastic goods where taxes raise revenue without major demand collapse.

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Market Analysis

Analysts use PED to predict consumer behavior during supply shocks, inflation, or competitor price changes — essential for forecasting revenue and market share under any pricing scenario.

Price elasticity of demand infographic showing demand curves for elastic vs inelastic goods, the PED spectrum from 0 to infinity, and revenue impact by elasticity type

PED spectrum from perfectly inelastic (PED=0) to perfectly elastic (PED=∞), with revenue impact and real-world examples. See classification table →

The PED Formula: Point vs Midpoint Method

There are two standard ways to calculate price elasticity of demand. The point method is simpler but gives different values depending on which direction you measure the change. The midpoint method (also called the arc elasticity formula) solves this by using the average of the two values as the base — giving the same result regardless of direction.

① Point Method (Basic Formula)

Use when: you have percentage changes directly.

PED = %ΔQ_d%ΔP

Symbol	Meaning	Example
PED	Price Elasticity of Demand (negative for normal goods)	−1.5
%ΔQ_d	Percentage change in quantity demanded	−15% (quantity fell)
%ΔP	Percentage change in price	+10% (price rose)

Point method example: Price rises 10%, quantity demanded falls 15%:
PED = −15% / +10% = −1.5 (elastic demand)
|PED| = 1.5 > 1: This product has elastic demand. Raising price will decrease total revenue.

② Midpoint Method (Arc Elasticity) — Used by this Calculator

Use when: you have actual prices and quantities (more accurate, direction-independent).

E_d = Q₂ − Q₁(Q₁ + Q₂) / 2P₂ − P₁(P₁ + P₂) / 2

Symbol	Meaning	Example
P₁, P₂	Original price and new price	$10 and $12
Q₁, Q₂	Original quantity and new quantity demanded	1,000 and 800 units
E_d	Price Elasticity of Demand (midpoint)	→ −1.22

Midpoint example: Price: $10→$12; Quantity: 1,000→800 units
%ΔQ = (800−1000)/900 = −22.2% | %ΔP = (12−10)/11 = +18.2%
PED = −22.2% / 18.2% = −1.22 — same result whichever direction you compute.

Types of Elasticity: Classification Guide

The absolute value of PED (ignoring the negative sign, since normal goods always have PED ≤ 0) determines how demand is classified. This classification directly predicts how revenue will respond to price changes.

Type	\|PED\|	Meaning	Revenue Impact	Real-World Examples
Perfectly Inelastic	= 0	Quantity never changes regardless of price	Price ↑ → Revenue always ↑	Insulin, emergency surgery, addictive substances
Inelastic	0 – 1	Qty drops less than price rises proportionally	Price ↑ → Revenue ↑	Gasoline (~0.2), cigarettes (~0.4), alcohol (~0.5)
Unit Elastic	= 1	Qty drops exactly proportionally to price rise	Price change → Revenue unchanged	Theoretical threshold — revenue is maximized here
Elastic	> 1	Qty drops more than price rises proportionally	Price ↑ → Revenue ↓	Luxury goods (~2.5), airline seats (~1.8), fast food (~1.5)
Perfectly Elastic	= ∞	Any price increase → zero quantity demanded	Must match market price exactly	Perfect commodity markets, standardized financial instruments

Elasticity & Total Revenue: The Key Relationship

The relationship between price elasticity and total revenue (TR = Price × Quantity) is the most practically important application of PED for businesses. The rule is counterintuitive but mathematically exact: raising price on inelastic products increases revenue, while raising price on elastic products destroys it.

TR = P × Q | ΔTR = P × (1 + E_d) × ΔP × Q

Scenario	PED	Price Action	Revenue Effect	Why
Inelastic demand	0.3	Raise 10%	↑ +7.3%	Qty only drops 3% — less than price up
Inelastic demand	0.3	Cut 10%	↓ −7.3%	Qty only rises 3% — less than price down
Unit elastic	1.0	Any change	→ No change	Qty change exactly offsets price change
Elastic demand	1.5	Raise 10%	↓ −5%	Qty drops 15% — more than price up
Elastic demand	1.5	Cut 10%	↑ +5%	Qty rises 15% — more than price down
Perfectly elastic	∞	Raise any	→ Zero	All customers switch to alternatives

🔑 The Revenue-Maximizing Price

Total revenue is maximized where PED = −1 (unit elastic). At this point, the loss from selling fewer units exactly offsets the gain from the higher price. Any price above this point moves into elastic territory (raising prices cuts revenue); any price below moves into inelastic territory. Use the Revenue Optimizer mode above to find where your pricing sits on this curve.

Cross & Income Elasticity of Demand

Elasticity extends beyond price-demand relationships. Two related concepts are equally important for competitive analysis and demand forecasting.

Cross Price Elasticity (XED)

Measures how demand for Good Y responds to a price change in Good X.

XED = %ΔQ_Y%ΔP_X

XED Sign	Relationship	Examples
Positive (+)	Substitute Goods	Pepsi & Coca-Cola, butter & margarine, Tea & Coffee
Negative (−)	Complementary Goods	Cars & gasoline, printers & ink, Netflix & smart TVs
Zero (≈0)	Unrelated Goods	Bread & tennis rackets, milk & airplane tickets

Income Elasticity of Demand (YED)

Measures how demand changes when consumer income changes.

YED = %ΔQ_d%ΔIncome

Normal goods (YED > 0): demand rises with income — restaurants, vacations, luxury cars (YED ~2.0+).
Inferior goods (YED < 0): demand falls when income rises — instant noodles, secondhand clothing, bus rides.

What Determines Price Elasticity?

Understanding why some products are elastic and others inelastic helps businesses design products and pricing strategies proactively.

01

Availability of substitutes

The most powerful determinant. Products with many close substitutes (branded vs generic cola) have high PED — customers easily switch. Products with no alternatives (insulin, specific medications) have PED near 0.

02

Necessity vs luxury classification

Necessities (food, utilities, basic medicine) tend to be inelastic — consumers buy them regardless of price. Luxury goods (designer handbags, sports cars, exotic vacations) are elastic — consumers defer or skip when prices rise.

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Proportion of income spent

Goods that consume a large share of income are more elastic (cars, homes) because consumers are more sensitive to price changes. Small-ticket items (salt, matches, paper clips) are highly inelastic — the dollar saving isn't worth switching.

04

Time horizon

Elasticity increases with time. Short-run gasoline demand is inelastic (commuters must drive today). Long-run demand is more elastic — people buy fuel-efficient cars, move closer to work, or take public transit if prices stay high.

05

Addictive or habitual nature

Cigarettes (PED ≈ −0.4), alcohol, coffee, and prescription medications all show low price sensitivity. Once a consumption habit forms, demand becomes resistant to price increases.

Frequently Asked Questions

Why is price elasticity of demand negative?

By the law of demand, price and quantity demanded move in opposite directions — when price rises, demand falls. So the numerator (%ΔQ) and denominator (%ΔP) always have opposite signs, making PED negative for normal goods. By convention, economists often report the absolute value |PED| to focus on the magnitude of response rather than direction.

What is the midpoint method and why is it more accurate?

The basic (point) formula uses the original price/quantity as the base, giving different PED values depending on whether you measure a price increase vs a price decrease between the same two points. The midpoint method uses the average of both values as the base, so PED is the same regardless of which direction you're computing. This calculator uses the midpoint (arc elasticity) method for all calculations.

How does PED affect tax incidence?

Tax incidence — who actually bears the cost of a tax — depends on relative elasticities. If demand is more inelastic than supply, consumers bear most of the tax (e.g., gasoline tax). If demand is more elastic than supply, producers bear more of the tax. Governments intentionally tax inelastic goods to maximize revenue with minimum behavioral distortion.

What is a PED of −1.5 and what does it mean for pricing?

A PED of −1.5 means demand is elastic: a 1% price increase causes a 1.5% decrease in quantity demanded. The absolute value |PED| = 1.5 > 1. Revenue implication: raising this product's price will reduce total revenue. To increase revenue, the business should cut price — the 1.5% quantity gain will more than offset the lower per-unit margin.

Can price elasticity ever be positive?

For normal goods, PED is always negative. But two exceptions exist: (1) Giffen goods — theoretically, when rice or bread prices rise sharply in poverty contexts, extremely poor consumers buy more because they can no longer afford protein alternatives. (2) Veblen goods — luxury items like designer bags or supercars where higher price signals status and actually increases demand (conspicuous consumption).

How do I use the Midpoint Formula step-by-step?

Step 1: %ΔQ = (Q₂ − Q₁) / ((Q₁ + Q₂) / 2) × 100. Step 2: %ΔP = (P₂ − P₁) / ((P₁ + P₂) / 2) × 100. Step 3: PED = %ΔQ / %ΔP. Example: Price $10→$12 (Q: 1,000→800): %ΔQ = (800−1000)/900 = −22.2%; %ΔP = (12−10)/11 = +18.2%; PED = −22.2/18.2 = −1.22 (elastic).

Use Price Elasticity analysis alongside these tools for complete pricing and revenue strategy:

Profit Margin Calculator →
After modeling elasticity and revenue impact, verify whether the new price still generates sufficient margin. A price cut that boosts revenue could still destroy profit if costs are fixed.
Markup Calculator →
Businesses with inelastic demand products can command higher markups. Use markup analysis to translate your PED insights into concrete cost-plus pricing decisions.
Percentage Discount Calculator →
For elastic demand products, strategic discounting increases revenue. Model the exact price cut needed to hit a target revenue or volume, factoring in your known PED.
Commission Calculator →
Sales commission structures must account for price elasticity. If elastic demand means discounting closes deals, model how commission changes impact total earnings at the lower sale price.
Compound Interest Calculator →
Revenue gains from optimal pricing decisions, compounded over time through reinvestment, create exponential business growth. Model how sustained revenue improvement compounds over 5–20 years.
APY Calculator →
For businesses pricing financial products (loan rates, deposit rates), APY and PED interact: small rate changes on inelastic financial products represent guaranteed revenue without customer loss.