Marginal cost and marginal revenue are economic measurements used to determine the effects of producing one more unit in a production system. Companies typically look to reach a production equilibrium where marginal cost and marginal revenue are equal. At this point, the company will maximize its profit. The relationship between these two economic concepts is important, as an imbalance on either side can result in production inefficiencies. When an imbalance occurs, companies will experience an economy of scale.

Marginal cost increases when total cost changes by producing one additional unit. For example, 50 units cost $100 US Dollars (USD) to produce. A cost increase to $110 USD from producing 101 units indicates a marginal cost of $10 USD for the 101st unit. Each additional unit produced will go through this measurement in order to determine the marginal cost of additional products. Companies can compare the marginal cost and marginal revenue increase as part of a cost-benefit analysis.

The marginal revenue formula is a bit different than the marginal cost calculation. For example, a company can sell 10 units for $15 USD. Selling 11 units will reduce the selling price to $14 USD. The marginal revenue is $150 USD (10 x $15 USD), less $154 USD (11 x $14 USD). Marginal revenue for this product is, therefore, $4 USD.

A comparison between the marginal cost and marginal revenue figures in this example is $10 USD in cost versus $4 USD in revenue. The company will lose $6 USD dollars by increasing its production by just one unit. This creates an equilibrium that is unsustainable for long-term production operations. Companies will, therefore, need to find another way for increasing marginal revenue when increasing production output. To figure out the equilibrium between marginal cost and marginal revenue, companies will test multiple production increase figures to maximize profit.

Short-term and long-term marginal cost and marginal revenue calculations are different. Fixed costs are included in short-run calculations. In long-term calculations, however, fixed costs do not affect marginal cost and marginal revenue. Economists consider fixed costs sunk in the long term; this means the company cannot recover the cost regardless of profit earned from sales.

Economies of scale are another factor in this production estimate relationship. This economic theory states that companies will begin to incur economic disadvantages when increasing production. One reason for this comes from limited consumer demand. Consumers often have fixed income in economic terms. They must make decisions to maximize utility by purchasing goods that result in the greatest value of money spent. Overproducing goods result in high supply and carrying costs with no offsetting consumer demand.