If demand increases and supply simultaneously decreases, equilibrium price will rise

How is equilibrium price determined?

Updated 7/8/2018 Jacob Reed
Below is a review of how markets reach equilibrium. If you would like to get some practice with these concepts, head over to the Shifting Markets Review Game.

What is equilibrium?

Equilibrium is the price that clears the market. In other words it is the price where quantity supplied equals quantity demanded. Market forces push prices toward equilibrium. 

If demand increases and supply simultaneously decreases, equilibrium price will rise

If demand increases and supply simultaneously decreases, equilibrium price will rise
Price Above Equilibrium

How does the market move toward equilibrium?

If the market price is above equilibrium, quantity supplied will be greater than quantity demanded; creating a surplus. When that occurs, market forces push the price downward toward equilibrium (increasing Qd and decreasing Qs) until the surplus is eliminated.

​If the market price is below equilibrium, quantity supplied will be less than quantity demanded; creating a shortage. When that occurs, market forces pull the price upward toward equilibrium (decreasing Qd and increasing Qs) until the shortage is eliminated.

If demand increases and supply simultaneously decreases, equilibrium price will rise
Price Below Equilibrium

How do shifts in supply and demand change equilibrium?

Shifts in supply or demand curves move the equilibrium price and quantity. If demand increases, equilibrium price and quantity both increase. If demand decreases, equilibrium price and quantity both decrease. If supply increases, equilibrium price decreases, and quantity increases. If supply decreases, equilibrium price increases and equilibrium quantity decreases. 
Note: If you don’t recall what shifts supply and demand, go review your demand and supply shifters.

How do double shifts impact price and quantity?

When supply and demand both shift, either price or quantity will be indeterminate. When supply and demand move in the same direction, price is indeterminate. That is because an increase in supply decrease price while an increase in demand will increase price. Since the price axis moves in both directions, the net effect is based on which shift is stronger. Since that cannot be known, the price will be indeterminate. Since both shifts increase equilibrium quantity, the quantity will definitely increase. 

Similarly, when supply and demand move in opposite directions, quantity is indeterminate because one shift will increase quantity and the other will decrease quantity. 

The key to figuring out the impact of double shifts is to graph out both shifts and see what happens to the equilibrium price and quantity with each shift. If the shifts conflict, that axis is indeterminate.

Supply and Demand is an economic model of price determination in a market. It concludes that in a competitive market, the unit price for a particular good will vary until it settles at a point where the quantity demanded by consumers will equal the quantity supplied by producers resulting in an economic equilibrium of price and quantity. This relationship between supply and demand can be seen in a plot of the classic supply-demand curve on the right. [1]

Definition: The law of supply and demand is a theory that explains the interaction between the sellers of a resource and the buyers for that resource.

If demand increases and supply simultaneously decreases, equilibrium price will rise

What are the Supply and Demand Laws?

The Supply and Demand model has two “laws,”: the (1) Law of Demand and the (2) Law of Supply. These laws interact with each other to determine the market price and volume of goods. The key components to the theory are:

Supply and Demand Outcomes

The four (4) basic outcomes of supply and demand are: [3]

  • If demand increases and supply remains unchanged, a shortage occurs, leading to a higher equilibrium price.
  • If demand decreases and supply remains unchanged, a surplus occurs, leading to a lower equilibrium price.
  • If demand remains unchanged and supply increases, a surplus occurs, leading to a lower equilibrium price.
  • If demand remains unchanged and supply decreases, a shortage occurs, leading to a higher equilibrium price.

(1) What is the Law of Demand?

The Law of Demand refers to the number of products people are willing to buy at different prices at a specific time. The law states that the higher the product price, the fewer people will demand the product.  As a consumer, the higher a product costs, the less the amount of the product the consumer will purchase. This means the opportunity cost of buying that product goes down. [2]

Factors that influence the supply are:

  • Consumer Preference
  • Influence
  • Number of Sellers
  • Taxes and Regulations

(2) What is the Law of Supply?

Supply refers to the quantities of product manufacturers or owners are willing to sell at different prices at a specific time.  The higher the price will result in the higher quantity supplied. As a seller, the opportunity cost of each product is higher, so they want to sell more, and producers want to produce more. [1]

Factors that influence the supply are:

  • Labor and Materials costs
  • Technology availability
  • Number of sellers
  • Capacity
  • Taxes and Regulations

What is Supply and Demand Equilibrium?

The market price is the intersection of the demand price and quantities of products manufactured, and the intersection is called the equilibrium price or Market Clearing Price. The equilibrium price is the price at which the producer can sell all the units he wants to produce, and the buyer can buy all the units he wants.

If demand increases and supply simultaneously decreases, equilibrium price will rise

It is visualized on a chart at the intersection of the supply and demand curve. This intersection is the market price at which suppliers bring to market that same quantity of product that consumers will be willing to buy. They then say the Supply and Demand are in equilibrium.  [1]

Purpose of the Supply and Demand Theory

The purpose of the Supply and Demand theory is to help people, businesses, bankers, investors, entrepreneurs, economists, government, and others understand and predict conditions in the market for best optimization.

Example of the Supply and Demand Theory

What Is an Example of the Law of Supply and Demand?

A bread company wants to introduce a new french bread to its market at the best possible price. To ensure the lowest production price, the manufacturer gets bids from many suppliers to obtain the lowest possible price for manufacturing the new bread.  The lower the cost of the bread, the more profit the company can make if it determines the best price that sells the most quantity of bread. The equilibrium (Market Price) between the quantity of bread sold and the price should bring the most profit.

  • [1] Nickels and McHugh, “Understanding Business” McGraw-Hill Irwin 2010
  • Price Theory – Supply and Demand Lecture  

Updated: 8/9/2022

Rank: G17.5

What happens to equilibrium price when demand increases and supply decreases?

An increase in demand and a decrease in supply will cause an increase in equilibrium price, but the effect on equilibrium quantity cannot be detennined. 1. For any quantity, consumers now place a higher value on the good,and producers must have a higher price in order to supply the good; therefore, price will increase.

What happens if supply and demand increases at the same time?

If the increase in both demand and supply is exactly equal, there occurs a proportionate shift in the demand and supply curve. Consequently, the equilibrium price remains the same. However, the equilibrium quantity rises. In such a case, the right shift of the demand curve is more relative to that of the supply curve.

What would happen to the equilibrium price and quantity if both demand and supply increase simultaneously?

Q. "If the demand and supply of a commodity both increase, the equilibrium price may not change, may increase, may decrease."

What happens to price when supply and demand change simultaneously?

Answer: In case of simultaneous changes in demand and supply, if the increase in demand is more than the increase in supply, then as we have seen in Fig. 1(b) above, the new equilibrium price becomes higher than the original equilibrium price.