Loading the player...

What is the 'Long Run'

The long run is a period of time in which all factors of production and costs are variable. In the long run, firms are able to adjust all costs, whereas, in the short run, firms are only able to influence prices through adjustments made to production levels. Additionally, while a firm may be a monopoly in the short term, they may expect competition in the long run.

In economics, long-run models may shift away from short-run equilibrium, in which supply and demand react to price levels with more flexibility.


The long run is a time period during which a manufacturer or producer is flexible in its production decisions. For example, a business with a one-year lease will have its long run defined as any period longer than a year since it’s not bound by the lease agreement after that year. In the long run, the amount of labor, size of the factory, and production processes can be altered if need be. Businesses can either expand or reduce production capacity or enter or exit an industry based on expected profits. Firms examining the long run understand that they cannot alter levels of production in order to reach an equilibrium between supply and demand.

In response to expected economic profits, firms can change production levels. For example, a firm may implement change by increasing (or decreasing) the scale of production in response to profits (or losses), which may entail building a new plant or adding a production line.

The short run, on the other hand, is the time horizon over which factors of production are fixed, except for labor, which remains variable.

In macroeconomics, the long run is the period when the general price level, contractual wage rates, and expectations adjust fully to the state of the economy, in contrast to the short run when these variables may not fully adjust.

Long Run Costs

As explained above, the scale of production can change in the long run, which means that all costs are variable in the long run. In the long run, a firm will search for the production technology that allows it to produce the desired level of output at the lowest cost. If a company is not producing at its lowest cost possible, it may lose market share to competitors that are able to produce and sell at minimum cost.

Economies of scale refers to the situation where, as the quantity of output goes up, the cost per unit goes down. In effect, economies of scale are the cost advantages that are achieved when there is an expansion of the size of production. The cost advantages translate to improved efficiency in production, which can give a business a competitive advantage in its industry of operations, which, in turn, could translate to lower costs and higher profits for the business.

The long run is associated with the long-run average (total) cost (LRAC or LRATC), the average cost of output feasible when all factors of production are variable. The LRAC curve is the curve along which a firm would minimize its cost per unit for each respective long-run quantity of output. As long as the LRAC curve is declining, then internal economies of scale are being exploited. If LRAC is falling when output is increasing, then the firm is experiencing economies of scale. When LRAC eventually starts to rise then the firm experiences diseconomies of scale, and, if LRAC is constant, then the firm is experiencing constant returns to scale.

The long-run average cost curve is comprised of a group of short-run average cost (SRAC) curves, each of which represents one specific level of fixed costs. The LRAC curve will, therefore, be the least expensive average cost curve for any level of output.

Market Entry and Exit in the Long Run

The number of firms in an industry is variable in the long run, as competitors may enter or exit an industry depending on the levels of profit previously seen by companies operating in that industry. A firm may decide to enter a market in response to expected profits, or exit a market in response to expected losses. The profit expectations in a market may be due to a change in consumers’ sensitivity to price changes, thus, price elasticity of demand in the long run may vary.

Conversely, barriers to entry prevent competitors from quickly entering a market in the short run.

  1. Minimum Efficient Scale

    The minimum efficient scale is the least amount of production ...
  2. Long Run Incremental Cost - LRIC

    Long run incremental cost (LRIC) refers to the the changing costs ...
  3. Operating Cost

    Operating costs are expenses associated with the maintenance ...
  4. Fixed Cost

    A fixed cost is an expense that remains the same regardless of ...
  5. Variable Cost

    A variable cost is a corporate expense that changes in proportion ...
  6. Aggregate Supply

    Aggregate supply is the total supply of goods and services produced ...
Related Articles
  1. Investing

    Understanding Marginal Cost of Production

    Marginal cost of production is an economics term that refers to the change in production costs resulting from producing one more unit.
  2. Insights

    What Are Economies Of Scale?

    Is bigger always better? Read up on the important and often misunderstood concept of economies of scale.
  3. Insights

    Understanding The Treasury Yield Curve Rates

    Treasury yield curves are a leading indicator for the future state of the economy and interest rates.
  4. Managing Wealth

    Is Pressing The Trade Just Pressing Your Luck?

    Scaling up into a trade can be a lucrative strategy, but you need to understand the risks involved.
  5. Investing

    Understanding Treasury Yield And Interest Rates

    By understanding the factors that influence treasury yield and interest rates, you can learn to anticipate their movement and profit from it.
  6. Investing

    A Flattening Yield Curve Is Good For The Economy and Stocks

    Wall Street is concerned because the yield curve is flattening, but that doesn't mean a recession is near.
  7. Investing

    Should U.S. Producers Shut Down While Oil Is out of the Money?

    Should oil producers simply stop producing and wait for oil prices to recover? It may make sense for some producers to shut down in a $40 per barrel oil price environment.
  8. Insights

    A Practical Look At Microeconomics

    Learn how individual decision-making turns the gears of our economy.
  9. Investing

    Calculating Economic Profit

    Economic profit is the difference between the revenue a firm earns from sales and the firm’s total opportunity costs.
  1. Do production costs include all fixed and variable costs?

    Learn more about fixed and variable costs and how they affect production costs. Understanding how to graph these costs can ... Read Answer >>
  2. How Do Fixed and Variable Costs Affect the Marginal Cost of Production?

    Learn about the marginal cost of production and how it is affected by changes in fixed and variable costs. Read Answer >>
  3. How are fixed costs treated in cost accounting?

    Learn how fixed costs and variable costs are used in cost accounting to help a company's management with budgeting and controlling ... Read Answer >>
  4. How is the shutdown point of a business determined?

    Find out what a shutdown point is and what financial metric determines whether a business has reached their shutdown point, ... Read Answer >>
  5. What are some examples of economies of scale?

    Take a look at different examples of economies of scale, including how marginal costs can be reduced through external and ... Read Answer >>
  6. How do fixed costs and variable costs affect gross profit?

    Learn about the differences between fixed and variable costs and find out how they affect the calculation of gross profit ... Read Answer >>
Trading Center