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Shift in supply

We know that a supply curve shows the minimum price a firm will accept to produce a given quantity of output. What happens to the supply curve when the cost of production goes up? Following is an example of a shift in supply due to a production cost increase.

Step 1. Draw a graph of a supply curve for pizza. Pick a quantity (like Q 0 ). If you draw a vertical line up from Q 0 to the supply curve, you will see the price the firm chooses. An example is shown in [link] .

Suppy curve

The graph represents the directions for step 1. A supply curve shows the minimum price a firm will accept (P sub 0) to supply a given quantity of output (Q sub 0).
The supply curve can be used to show the minimum price a firm will accept to produce a given quantity of output.

Step 2. Why did the firm choose that price and not some other? One way to think about this is that the price is composed of two parts. The first part is the average cost of production, in this case, the cost of the pizza ingredients (dough, sauce, cheese, pepperoni, and so on), the cost of the pizza oven, the rent on the shop, and the wages of the workers. The second part is the firm’s desired profit, which is determined, among other factors, by the profit margins in that particular business. If you add these two parts together, you get the price the firm wishes to charge. The quantity Q0 and associated price P0 give you one point on the firm’s supply curve, as shown in [link] .

Setting prices

The graph represents the directions for step 2. For a given quantity of output (Q sub 0), the firm wishes to charge a price (P sub 0) equal to the cost of production plus the desired profit margin.
The cost of production and the desired profit equal the price a firm will set for a product.

Step 3. Now, suppose that the cost of production goes up. Perhaps cheese has become more expensive by $0.75 per pizza. If that is true, the firm will want to raise its price by the amount of the increase in cost ($0.75). Draw this point on the supply curve directly above the initial point on the curve, but $0.75 higher, as shown in [link] .

Increasing costs leads to increasing price

The graph represents the directions for step 3. An increase in production cost will raise the price a firm wishes to charge (to P sub 1) for a given quantity of output (Q sub 0).
Because the cost of production and the desired profit equal the price a firm will set for a product, if the cost of production increases, the price for the product will also need to increase.

Step 4. Shift the supply curve through this point. You will see that an increase in cost causes an upward (or a leftward) shift of the supply curve so that at any price, the quantities supplied will be smaller, as shown in [link] .

Supply curve shifts

The graph represents the directions for step 4. An increase in the cost of production will shift the supply curve vertically by the amount of the cost increase.
When the cost of production increases, the supply curve shifts upwardly to a new price level.

Summing up factors that change supply

Changes in the cost of inputs, natural disasters, new technologies, and the impact of government decisions all affect the cost of production. In turn, these factors affect how much firms are willing to supply at any given price.

[link] summarizes factors that change the supply of goods and services. Notice that a change in the price of the product itself is not among the factors that shift the supply curve. Although a change in price of a good or service typically causes a change in quantity supplied or a movement along the supply curve for that specific good or service, it does not cause the supply curve itself to shift.

Factors that shift supply curves

The graph on the left lists events that could lead to increased supply. The graph on the right lists events that could lead to decreased supply.
(a) A list of factors that can cause an increase in supply from S 0 to S 1 . (b) The same factors, if their direction is reversed, can cause a decrease in supply from S 0 to S 1 .

Because demand and supply curves appear on a two-dimensional diagram with only price and quantity on the axes, an unwary visitor to the land of economics might be fooled into believing that economics is about only four topics: demand, supply, price, and quantity. However, demand and supply are really “umbrella” concepts: demand covers all the factors that affect demand, and supply covers all the factors that affect supply. Factors other than price that affect demand and supply are included by using shifts in the demand or the supply curve. In this way, the two-dimensional demand and supply model becomes a powerful tool for analyzing a wide range of economic circumstances.

Key concepts and summary

Economists often use the ceteris paribus or “other things being equal” assumption: while examining the economic impact of one event, all other factors remain unchanged for the purpose of the analysis. Factors that can shift the demand curve for goods and services, causing a different quantity to be demanded at any given price, include changes in tastes, population, income, prices of substitute or complement goods, and expectations about future conditions and prices. Factors that can shift the supply curve for goods and services, causing a different quantity to be supplied at any given price, include input prices, natural conditions, changes in technology, and government taxes, regulations, or subsidies.


[link] shows information on the demand and supply for bicycles, where the quantities of bicycles are measured in thousands.

Price Qd Qs
$120 50 36
$150 40 40
$180 32 48
$210 28 56
$240 24 70
  1. What is the quantity demanded and the quantity supplied at a price of $210?
  2. At what price is the quantity supplied equal to 48,000?
  3. Graph the demand and supply curve for bicycles. How can you determine the equilibrium price and quantity from the graph? How can you determine the equilibrium price and quantity from the table? What are the equilibrium price and equilibrium quantity?
  4. If the price was $120, what would the quantities demanded and supplied be? Would a shortage or surplus exist? If so, how large would the shortage or surplus be?
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The computer market in recent years has seen many more computers sell at much lower prices. What shift in demand or supply is most likely to explain this outcome? Sketch a demand and supply diagram and explain your reasoning for each.

  1. A rise in demand
  2. A fall in demand
  3. A rise in supply
  4. A fall in supply

Got questions? Get instant answers now!


Landsburg, Steven E. The Armchair Economist: Economics and Everyday Life . New York: The Free Press. 2012. specifically Section IV: How Markets Work.

National Chicken Council. 2015. "Per Capita Consumption of Poultry and Livestock, 1965 to Estimated 2015, in Pounds." Accessed April 13, 2015. http://www.nationalchickencouncil.org/about-the-industry/statistics/per-capita-consumption-of-poultry-and-livestock-1965-to-estimated-2012-in-pounds/.

Wessel, David. “Saudi Arabia Fears $40-a-Barrel Oil, Too.” The Wall Street Journal . May 27, 2004, p. 42. http://online.wsj.com/news/articles/SB108561000087822300.

Questions & Answers

a. Assume that Good X is a Giffen good, illustrate and explain the income and substitution effects for a decrease in the price of good X.
Thulisa Reply
as price of good X(assume as Griffen good) decrease income of the consumer increase , consumer will demand other goods rather than the Griffen goods thus at lower prices of good X it's demand will decrease.
what is law of demand
Hugo Reply
what is the law of demand
What is the law of demand
just considering the relationship between price and quantity, holding other factors constant.
when the price of a commodity increases, it's demand will decrease. and when the price of a commodity decreases, it's demand will increase, other things remaining the same or constant. That is called Law of Demand.
other things remained constant there is inverse relationship between price and quantity demand i .e when price of a commodity increased the demand of quantity will decrease and vice- versa.
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Ibrahim Reply
it is a paradoxical situation, where two individuals acts for their self interest but don't achieve the optimal point.
gays why we add Griffen goods in aggregate demand as we know Griffen goods have positive relationships that means if price increase demand of goods also increase .but in aggregate demand there is a negative relationship between price and aggregate output.
explain the determinants of derive demand?
what financial market is all about
Emmanuel Reply
What happens to the ppf curve due to following events a) A relaxation of policies allowing more foreign direct investment into the country b) Increasing the minimum wage level c) A decrease in expenditure on research and development d) An increase in the retirement age
luvi Reply
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Discuss various from the imperfect competition
ZuBaIr Reply
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tell me the defference between budget constraint and limited resources
Emmanuel Reply
budget constraint is the sub-part of limited resources. budget constraint can be for extreme short period of time like few hours but same is not true for the limited resources.
what is budget constraint?
Emmanuel Reply
Budget constraint refers to all the combinations of goods and services which an individual can buy on a given price and with his given income.
what are the job markets for an economist?
Emmanuel Reply
An economist can serve as a consultant in a bank, whether commercial or governmental. He can also works as a Professor in the University, analyst and forecaster and other sectors of the society
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Emmanuel Reply
You'll need knowledge in calculus
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Laxman Reply
What is taste and preferences
Jacjac Reply
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Ankita Reply
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BtsARMY Reply
a dire need of something
by consumers
such as the quality of life
Demand simply means the amount of goods and services a consumer is willing to purchase at a given price level at a given period of time in the markets.
quantity of goods or services a buyer willing to buy at certain period of time give other things are equal. Or it is simply the willing + the ability.
What is income effect? please tell friends 🙏
Income effect simply defines how the change in price can change in the quantity that consumer will demand of that good . It means if price increases the demand to buy that good decreases because price of a good directly effects on real income.
change in price and the effect on quantity demanded.

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