A good is elastic when a change in its price causes a proportionally larger change in how much people buy. If the price of a product rises by 10% and the quantity people purchase drops by more than 10%, that product has elastic demand. The concept is one of the most practical ideas in economics because it explains why some businesses thrive by raising prices while others would lose money doing the exact same thing.
The Elasticity Coefficient
Economists measure elasticity with a simple ratio: the percent change in quantity demanded divided by the percent change in price. The result is called the elasticity coefficient. When that number is greater than 1, demand is elastic. When it’s less than 1, demand is inelastic. And when it lands exactly at 1, economists call it “unit elastic.”
Here’s a concrete example. Say a product’s price drops from $10 to $8, and the quantity sold jumps from 30 units to 50 units. The price fell by 20%, but the quantity increased by about 67%. That gives an elasticity coefficient of roughly 2.25, well above 1, making this a clearly elastic good. Buyers reacted strongly to the price change.
Why It Matters for Revenue
Elasticity directly determines whether a business makes more or less money by changing its prices. For an elastic good, raising the price is a losing move. Because customers are highly sensitive to the price, a bump drives so many of them away that the lost sales outweigh the extra revenue per unit. The math works against you: you’re charging more per item, but selling far fewer items.
The reverse is also true. A business selling an elastic good can actually increase total revenue by lowering its price. The lower price attracts enough new buyers to more than compensate for the smaller profit margin on each sale. This is why movie theaters, airlines, and retailers run frequent discounts on products where consumers can easily go elsewhere. They know their customers are price-sensitive, so pulling people in with lower prices is more profitable than squeezing higher prices out of a shrinking customer base. Total revenue is maximized at the point where demand is unit elastic, right at the boundary between elastic and inelastic.
What Makes a Good Elastic
Several factors determine whether a good ends up elastic or inelastic. The most important is the availability of substitutes. When consumers can easily switch to a competing product, they will. Beef, pork, and poultry are classic examples. As poultry prices declined in recent years, consumers shifted away from beef and pork. Any product with close substitutes tends to have elastic demand because buyers aren’t locked in.
How much of your income a product consumes also matters. Something that takes up a tiny share of your budget, like a pack of gum, doesn’t trigger much price sensitivity. You probably wouldn’t change your buying habits if gum went up by 20 cents. But goods that represent a significant chunk of your spending, like a car payment or rent, make you far more attentive to price changes. The bigger the share of income, the more elastic the demand.
Luxuries tend to be more elastic than necessities. If you need insulin or electricity, you’ll pay whatever you have to. But if the price of a gold tiara doubles, you simply won’t buy one. You don’t need it, so you’re free to walk away. Consumer durables like washing machines and automobiles are particularly elastic because not only are they expensive, they’re also purchases you can postpone. If car prices spike, you can keep driving your current vehicle another year.
Time horizon plays a role too. In the short run, people are often stuck with their current choices. But given enough time, they find alternatives. Gasoline is a good example: a sudden price spike doesn’t immediately change how much you drive, but over months and years, people buy more fuel-efficient cars, move closer to work, or switch to public transit.
How Narrowly You Define the Market
One detail that trips people up is that elasticity depends heavily on how you define the product category. Broadly defined markets tend to be less elastic because there are fewer substitutes for the entire category. “Food” is inelastic because you have to eat. But narrow categories within that market can be very elastic. “Organic free-range chicken from a specific brand at a specific store” has plenty of substitutes, so its demand is highly elastic.
This is why brand-level competition behaves differently from category-level competition. Research from the Kellogg School of Management found that loyal consumers are less sensitive to price when choosing between brands, meaning brand loyalty reduces elasticity at the product level. If you’re devoted to a particular coffee brand, a small price increase won’t make you switch. But consumers without strong brand preferences are highly elastic, readily jumping to whatever’s cheapest. The same physical product can be elastic or inelastic depending on who’s buying it and how many alternatives they perceive.
Elastic vs. Inelastic at a Glance
- Elastic goods (coefficient greater than 1): many substitutes, often luxuries or big-ticket items, demand drops sharply when prices rise. Examples include restaurant meals, electronics, airline tickets, and name-brand clothing.
- Inelastic goods (coefficient less than 1): few substitutes, often necessities or small purchases, demand barely budges with price changes. Examples include gasoline, prescription medications, salt, and utilities.
The distinction isn’t always black and white. Most goods fall on a spectrum, and their elasticity can shift as market conditions, consumer preferences, and available alternatives change over time. But understanding where a product sits on that spectrum tells you a lot about how its market behaves, why certain businesses price the way they do, and how consumers respond when costs go up.