# Marginal Revenue Explained, With Formula and Example

## What Is Marginal Revenue?

Marginal revenue is the increase in revenue that results from the sale of one additional unit of output. While marginal revenue can remain constant over a certain level of output, it follows from the law of diminishing returns and will eventually slow down as the output level increases. In economic theory, perfectly competitive firms continue producing output until marginal revenue equals marginal cost.

### Key Takeaways

• Marginal revenue refers to the incremental change in earnings resulting from the sale of one additional unit.
• Analyzing marginal revenue helps a company identify the revenue generated from each additional unit sold.
• Marginal revenue is often shown graphically as a downward sloping line that represents how a company usually has to decrease its prices to drive additional sales.
• A company that is looking to maximize its profits will produce up to the point where marginal cost equals marginal revenue.
• When marginal revenue falls below marginal cost, firms typically do a cost-benefit analysis and halt production as it may cost more to sell a unit than what the company will receive as revenue.
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## Understanding Marginal Revenue

Marginal revenue is a financial and economic calculation that determines how much revenue a company earns in revenue for each additional unit sold. As the price of a good is often tied to market supply and demand, a company's marginal revenue often varies based on how many units it has already sold.

Marginal revenue is useful in several contexts. Companies use historical marginal revenue data to analyze customer demand for products in the market. They also use the information to set the most effective and efficient prices. Last, companies rely on marginal revenue to better understand forecasts; this information is then used to determine future production schedules such as material requirements planning.

## How to Calculate Marginal Revenue

A company calculates marginal revenue by dividing the change in total revenue by the change in total output quantity. Ideally, the change in measurements captures the change from a single quantity to the next available quantity (i.e. the difference between the 100th and 101st unit sold). However, the formula above can still be used to capture the average marginal revenue across a series of units (i.e. the difference between the 100th and 115th unit sold).

The formula for marginal revenue can be expressed as:

\begin{aligned}\text{Marginal Revenue}&=\frac{\text{Change in Revenue}}{\text{Change in Quantity}}\\\\[-9pt]MR&=\frac{\Delta TR}{\Delta Q}\end{aligned}

## Marginal Revenue vs. Marginal Cost

Any benefits gained from adding the additional unit of activity are marginal benefits. One such benefit occurs when marginal revenue exceeds marginal cost, resulting in a profit from new items sold. If the sale of one additional unit yields marginal revenue of $100 and marginal expenses of$80, the company will receive marginal profit of $20 for the additional item sold. A company experiences the best results when production and sales continue until marginal revenue equals marginal cost. Beyond that point, the cost of producing an additional unit will exceed the revenue generated. If the company sells one additional unit for$100 but incurs marginal revenue of $105, the company will lose$5 in the process of selling that extra unit.

When marginal revenue falls below marginal cost, firms typically adopt the cost-benefit principle and halt production, as no further benefits are gathered from additional production.

A perfectly competitive firm can sell as many units as it wants at the market price, whereas the monopolist can do so only if it cuts prices for its current and subsequent units.

## Competitive Firms vs. Monopolies

Marginal revenue for competitive firms is typically constant. This is because the market dictates the optimal price level and companies do not have much—if any—discretion over the price. As a result, perfectly competitive firms maximize profits when marginal costs equal market price and marginal revenue. Marginal revenue works differently for monopolies. For a monopolist, the marginal benefit of selling an additional unit is less than the market price.

A firm's average revenue is its total revenue earned divided by the total units. A competitive firm’s marginal revenue always equals its average revenue and price. This is because the price remains constant over varying levels of output. In a monopoly, because the price changes as the quantity sold changes, marginal revenue diminishes with each additional unit and will always be equal to or less than average revenue.

## What Is the Marginal Revenue Formula?

Marginal revenue is calculated as the change in revenue divided by the change in quantity for any two given levels of sales. The closer the two levels of sales, the more meaningful and precise the marginal revenue calculation will be.

For example, imagine a company will make an additional $1,000 if it increases sales from 200 to 220 goods. The average marginal revenue received for each of these additional 20 units is$50/each. Should the company receive an additional $800 for increasing sales from 220 to 240, the average marginal revenue for these 20 units is$40/each.

## Is Marginal Revenue the Same As Profit?

Marginal revenue only considers income received and does not reflect any marginal expenses required to manufacture or sell the goods. Therefore, marginal revenue is different from profit.

## What Is Marginal Revenue and Marginal Cost?

Marginal revenue is the income gained by selling one additional unit, while marginal cost is the expense incurred for selling that one unit. Each measure the incremental change in dollars between varying levels of sales to determine at what level a company is most efficiently producing and selling goods.

## Why Is Marginal Revenue Important?

Marginal revenue is important because it is a crucial indicator regarding the most idea level of activity a company should undertake. It is mathematically most ideal for a company to produce goods until marginal revenue is equal to marginal expenses; selling goods beyond this level usually means more expenses are incurred than revenue received for each good.

## What Does It Mean If Marginal Revenue Is Negative?

If marginal revenue is negative, this means total revenue falls as additional units are sold. This may be the result of a company needing to cut prices to sell those additional units. In this case, strictly looking at just marginal revenue, it is more ideal for a company to have sold less goods but for a higher average price as more revenue would have been received.

## The Bottom Line

Regardless of its sector, industry, or product line, companies must be aware of how increasing sales quantities impacts marginal revenue. If the company must decrease prices to generate additional sales, marginal revenue will slowly decrease to the point where it is no longer profitable to sell additional goods.