Everything a student needs to understand inelastic price elasticity of demand — clear definition, simple formula, real-life examples, demand curve diagram, and comparison with elastic demand.
When petrol prices rise, most people still fill up their cars. When luxury hotel prices rise, guests start booking cheaper alternatives. This difference is exactly what inelastic price elasticity describes — and understanding it is essential for any Economics exam.
Price elasticity of demand (PED) measures how much the quantity demanded of a good changes when its price changes. Inelastic price elasticity means demand barely responds to a price change — consumers keep buying roughly the same amount even when the price goes up or down.
The price change is proportionally bigger than the change in how much people buy. That is the core idea.
✓ The simple test: Would you still buy this thing if the price went up by 20%? If yes → it is probably inelastic. If you would switch to something else → it is probably elastic.
A price elastic and inelastic definition together: elastic demand is when consumers are very sensitive to price (PED > 1). Inelastic demand is when they are not very sensitive (PED < 1). Every good sits somewhere on this spectrum.
⚠️ About the minus sign: PED is almost always negative — when price rises, quantity demanded falls. Most exam boards ask you to use the absolute value (ignore the minus sign) and compare to 1. A PED of −0.4 is written as |PED| = 0.4, which is inelastic.
Every good sits somewhere on this spectrum. The number you calculate tells you exactly where.
The shape of the demand curve tells you whether a good is elastic or inelastic at a glance. Study both diagrams carefully — you need to draw these in your exam.
📌 Exam diagram tip: Always label both axes (Price on the Y-axis, Quantity on the X-axis). Label your curve “D”. Show dashed lines for the price change and the resulting quantity change. This picks up method marks even if your curve shape is not perfect.
The price of petrol rises from £1.50 to £1.80 per litre. Quantity demanded falls from 10,000 to 9,400 litres per day. Calculate PED and state whether demand is elastic or inelastic.
% change in price: (1.80 − 1.50) ÷ 1.50 × 100 = +20%
% change in quantity demanded: (9,400 − 10,000) ÷ 10,000 × 100 = −6%
Apply formula: PED = −6% ÷ +20% = −0.3
|PED| = 0.3 — this is less than 1, so demand is inelastic
A 20% price rise only caused a 6% fall in demand. People still buy petrol because they need it — few alternatives exist in the short run.
Here is an infographic-style breakdown of common goods. Each card shows whether it is elastic or inelastic, the typical PED range, and the reason why.
Addictive product. Smokers keep buying even after large price rises.
|PED| ≈ 0.3 – 0.5 Addiction + no substitute for nicotineMost drivers need petrol and cannot quickly switch in the short run.
|PED| ≈ 0.2 – 0.4 Necessity + few alternatives short-termPatients must buy essential medicines regardless of price.
|PED| ≈ 0.1 – 0.3 Necessity + no substitutesHabit-forming for regular drinkers. Demand does not fall much when taxed.
|PED| ≈ 0.4 – 0.7 Habit / addiction factorBasic food ingredient. Households keep buying even if prices rise moderately.
|PED| ≈ 0.3 – 0.6 Necessity + small share of incomeHabitual consumption makes regular buyers less sensitive to price changes.
|PED| ≈ 0.6 – 0.9 Habit — near the boundaryDesigner bags, luxury hotels, sports cars — non-essential with many alternatives.
|PED| > 1 Non-essential + many substitutesMany competing brands. A price rise causes consumers to switch to alternatives.
|PED| > 1 Many substitutes availableConsumers can eat at home instead. Price-sensitive and substitutable.
|PED| > 1 Not essential + easy alternatives📚 Struggling with PED exam questions? Our GCSE Economics tutors and A Level Economics tutors work through real past paper questions — step by step.
Book Free SessionGoods people must have to live — food, water, energy, medicine. Demand stays strong even when prices rise.
When there is no alternative product, consumers cannot switch. No substitute = more inelastic.
Cigarettes, alcohol, and caffeine create habitual demand. Consumers find it hard to cut back even at higher prices.
If a good costs very little relative to income (like salt or matches), even a big % price rise barely hurts the wallet.
In the short run consumers cannot adapt. Over time they find alternatives and demand becomes more elastic.
Strong loyalty to a brand (Apple, Nike) means consumers keep buying even if prices rise — they see no real alternative.
📚 Revenue rule — must know for exams: If demand is inelastic and a business raises prices, total revenue goes up because the fall in quantity sold is smaller than the price rise. Formula: Total Revenue = Price × Quantity.
✓ Exam tip: When asked “how might a government use PED to decide which goods to tax?” — say: goods with inelastic demand raise more revenue because quantity barely falls when prices rise. Always give cigarettes or petrol as your example.
Use this checklist in your exam when you need to decide whether a good is elastic or inelastic. More boxes that point to inelastic → the good is inelastic.
Necessities → inelastic. Luxuries → elastic.
Few substitutes → inelastic. Many substitutes → elastic.
Yes (cigarettes, alcohol) → inelastic. No → could be elastic.
Tiny share (salt) → inelastic. Large share (holidays) → elastic.
Short run → more inelastic. Long run → more elastic as consumers adapt.
|PED| < 1 = inelastic | |PED| > 1 = elastic | |PED| = 1 = unit elastic
Our examiner-qualified GCSE and A Level Economics tutors cover price elasticity and every other economics topic — with real past paper practice and step-by-step feedback.
Book Your Free Consultation →Inelastic price elasticity means that when the price of a good changes, the quantity demanded changes by a proportionally smaller amount. The absolute value of PED is less than 1. Consumers keep buying the product even when prices rise because they need it or have few alternatives.
PED = % change in quantity demanded ÷ % change in price. For inelastic demand the absolute value of PED is between 0 and 1. For example PED = −0.4 means demand is inelastic — a price rise of 10% only reduces quantity demanded by 4%.
Elastic demand (|PED| > 1): a price change causes a proportionally larger change in quantity demanded. Demand curve is flat. Consumers are very price-sensitive. Inelastic demand (|PED| < 1): a price change causes a proportionally smaller change. Demand curve is steep. Consumers keep buying regardless of price.
Cigarettes are price inelastic (|PED| typically 0.3–0.5). Because they are addictive, smokers continue buying even after significant price rises. This is why governments impose heavy excise duties on cigarettes — the tax raises large revenue without dramatically reducing consumption.
Luxury goods are generally price elastic (|PED| > 1). They are non-essential with many substitutes. When prices rise, consumers cut back or switch to alternatives. Examples: designer handbags, luxury holidays, sports cars.
Oil is price inelastic in the short run (|PED| around 0.2–0.4). Most consumers and businesses cannot quickly find alternatives when prices rise. In the long run, demand becomes more elastic as people switch to electric vehicles or alternative energy. Always distinguish short run vs long run in your exam answer.
Sugar tends to be price inelastic. It is a basic food ingredient and households continue to buy it even if prices rise moderately. If prices rise substantially, some consumers switch to sweetener alternatives, making demand slightly more elastic at higher price points.
Alcohol demand varies by consumer. For habitual or heavy drinkers, demand is inelastic (|PED| around 0.4–0.7) due to habit-forming behaviour. For occasional drinkers, demand is more elastic. Overall alcohol is generally inelastic — which is why governments tax it heavily.
Perfectly inelastic demand (PED = 0) means quantity demanded does not change at all regardless of price. The demand curve is a perfectly vertical line. This is a theoretical extreme — example: life-saving medicine with no substitute. Mostly used for diagram practice and theoretical analysis in exams.
If you have data: calculate PED. |PED| < 1 = inelastic; |PED| > 1 = elastic. Without data, ask: Is it a necessity? Few substitutes? Addictive? Small share of income? Short time period? More “yes” answers point to inelastic demand. Luxury, many substitutes, large share of income = elastic.
Branded clothes are generally price elastic because many competing brands exist. A price rise for one brand causes consumers to switch to alternatives. However, brands with very strong loyalty (some luxury labels) can be more inelastic. In a competitive market, elasticity is higher for individual brands.
Coffee sits near the elastic/inelastic boundary (|PED| around 0.6–0.9 for regular drinkers). Habitual drinkers are somewhat inelastic. However, substitutes exist (tea, energy drinks), and premium cafe coffee is more elastic than basic home coffee. The type of coffee matters for your answer.
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