Demand (economics)

Demand is the quantity of a good or service consumers are willing and able to buy at different prices, over a specified period and under specified conditions.

Law of demand: The principle that, other things equal, a lower price leads to a higher quantity demanded and a higher price to a lower quantity demanded. It describes the usual inverse relationship between a good’s price and its quantity demanded.
Quantity demanded: The amount of a good consumers are willing and able to buy at a particular price and under specified conditions. It is the specific purchase amount represented by one point on a demand curve.
Market equilibrium: A market state in which the quantity supplied equals the quantity demanded at a given price. Market demand combines with supply to determine the equilibrium price and quantity.
Supply (economics): The quantity of a good or service producers are willing and able to sell at different prices. Supply describes sellers’ choices, which interact with demand to determine market outcomes.
Demand curve: A graph showing the quantity of a good consumers demand at each price, holding other factors constant. It represents demand across prices rather than at a single price.
Willingness to pay: The maximum amount a person is prepared to pay for a good or service. Buyers’ valuations help determine whether they are willing to purchase at a given price.
Tax incidence: The distribution of a tax’s economic burden between buyers and sellers, regardless of who legally pays it. Demand elasticity helps determine how much of a tax buyers bear.
Change in quantity demanded: A movement along a demand curve caused by a change in the good’s own price. It differs from a change in demand, which shifts the entire curve.
Income effect: The change in consumption caused by a price change altering a consumer’s purchasing power. A price change can affect purchases by changing what consumers can afford.
Consumer surplus: The difference between what consumers are willing to pay and what they actually pay. It measures the gains buyers receive from purchasing at market prices.

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Consumer sovereigntyRelated: Combined consumer choices form the demand firms use when deciding what to supply.