Marginal revenue shows how much total revenue changes when you sell one more unit. This guide explains how to calculate marginal revenue with the formula, walks through three worked examples, and shows how retailers apply the same logic to pricing decisions.
When sales increase by one unit, total revenue changes. Marginal revenue (MR) is the amount of that change. The standard marginal revenue definition is the change in total revenue that results from selling one additional unit.
Businesses use this measure to see what an extra sale actually adds to revenue. It can be particularly useful when evaluating sales volumes and pricing decisions.
MR is not necessarily the same as the product's selling price. The relationship between the two depends on how the business responds when it wants to sell more.
Price applies to an individual unit. Marginal revenue, on the other hand, is based on the change in total revenue.
The two match when a business can sell an additional unit at the existing price without changing anything else. If the company needs to reduce its price to sell more, the calculation changes. The lower price may apply to other units as well, reducing the amount of additional revenue generated by the extra sale.
The marginal revenue formula measures the change in total revenue relative to the change in quantity sold.
MR = ΔTR / ΔQ
Where:
If MR is positive, total revenue increases. If it is zero, total revenue remains unchanged. A negative MR means total revenue falls as sales increase.
This result is usually considered alongside marginal cost and demand. Price elasticity can also matter, particularly when a business needs to change its price to sell additional units.
Marginal revenue relates closely to three other metrics. Knowing how they differ helps make sure each one is applied and interpreted correctly.
|
Metric |
Definition |
Formula |
Relationship to marginal revenue |
|
Marginal revenue |
Revenue added by selling one more unit |
MR = ΔTR / ΔQ |
- |
|
Average revenue |
Revenue earned per unit sold |
AR = TR / Q |
Equals price when every unit sells at one price; MR falls below AR when extra volume requires a lower price |
|
Total revenue |
All income from sales |
TR = P × Q |
MR is the change in TR per extra unit; TR peaks where MR = 0 |
|
Marginal cost |
Cost of producing or buying one more unit |
MC = ΔTC / ΔQ |
Profit is maximized where MR = MC |
Table 1. Marginal revenue and related economic metrics.
Average revenue is calculated across the units a business has already sold, giving an average amount earned from each one. Marginal revenue is concerned with what happens after the next unit is added to those sales.
When every unit is sold at the same price, average revenue matches that price. MR may tell a different story if the company needs to offer a lower price in order to increase the number of units sold.
Total revenue represents the full income generated by a company's sales. Marginal revenue is about the difference between that total before and after one more unit is sold.
For this reason, the two figures answer different questions. Total revenue reflects the scale of sales overall, whereas MR helps show the financial effect of increasing the sales quantity.
Increasing output brings in additional revenue, but it can also create additional costs. Marginal revenue captures the first part, the extra income from selling another unit, while marginal cost measures the extra expense of producing or buying it.
Looking at marginal revenue and marginal cost together can help a business decide whether expanding sales is likely to add to profit. The comparison can also inform decisions on how to increase profit margin.
A demand curve maps out the prices associated with different quantities that consumers are willing to purchase. The marginal revenue curve takes the analysis a step further by showing the additional revenue associated with each increase in sales.
For a business facing downward-sloping demand, marginal revenue decreases more rapidly than price as output expands. This pattern is tied to price elasticity: the more responsive demand is to price changes, the greater the effect of a price adjustment on sales.
The formula becomes clearer when applied to different pricing and sales scenarios.
Start with a case where a lower price lifts sales. A retailer sells 1,000 packs of pasta at $5, then cuts the price to $4.80 and sells 1,100 packs. Revenue rises from $5,000 to $5,280.
MR = $280 / 100 = $2.80
In this marginal revenue example, the extra 100 units bring $280 of additional revenue. Because the lower price applies to every unit sold, MR is below the $4.80 price.
Now only the number of units changes. The product price stays at $10, while sales increase from 500 to 600 units, so revenue reaches $6,000 instead of $5,000.
MR = $1,000 / 100 = $10
The additional sales generate $1,000, or $10 per unit. When the price does not change, MR equals the price.
Finally, consider a price cut that sells more units but brings in less money. A retailer goes from selling 1,000 units at $10 to selling 1,200 units at $8. Revenue falls from $10,000 to $9,600.
MR = −$400 / 200 = −$2
Each additional unit reduces total revenue by $2 on average, because the discount on the 1,000 units that would have sold anyway outweighs the revenue from the extra 200. Whenever MR turns negative, the price cut is costing revenue as well as margin.
A business may sell more products without seeing the same increase in revenue. Marginal revenue helps find out why and make appropriate corrections.
The relationship between marginal revenue and marginal cost gives businesses a clear rule for additional volume. Adding volume makes sense while each extra unit brings in more revenue than it costs to produce or buy. Profit peaks where marginal revenue equals marginal cost; beyond that point, each extra unit reduces profit.
Lowering or raising a price can change sales volume as well as revenue per unit. Marginal revenue captures the effect of that change on total revenue. Businesses can also use pricing KPIs to track the wider results of their pricing decisions.
Changes in marginal revenue can reveal how customers respond as prices and sales volumes change. Tracking these changes helps businesses understand demand patterns and identify when increasing volume may require increasingly large price concessions.
Marginal revenue gives retailers a way to measure the revenue gained from an increase in sales, including when that increase comes with a price change.
Retailers can use marginal revenue analysis to assess whether a price change is likely to generate enough additional sales to offset the lower revenue per unit. Because retailers buy rather than produce, the cost side of the comparison is the unit purchase cost. This logic supports demand-based pricing and more advanced price optimization models, particularly when pricing decisions need to account for changing customer demand.
How much customers change their purchases after a price change matters for revenue. Price elasticity measures this change in demand and shows exactly why marginal revenue moves when prices change:
MR = P × (1 − 1 / |E|)
Here P is the price and |E| is the absolute value of the price elasticity of demand. At a price of $10 and an elasticity of −2, MR is $10 × (1 − 0.5) = $5. At an elasticity of −0.5, MR is $10 × (1 − 2) = −$10. When demand is elastic (|E| above 1), MR is positive and a price cut can grow revenue. When demand is inelastic (|E| below 1), MR is negative and a price cut reduces revenue.
Competera Pricing Platform models price elasticity and cross-product effects to forecast the revenue and margin impact of a price change before it goes live.
See how Competera forecasts the impact of every price change
Marginal revenue and marginal cost analysis provides a useful economic framework, but applying it across thousands of products requires models that can account for complex and changing demand patterns. Competera Pricing Platform extends this logic across the retail portfolio by using demand signals and product relationships to inform pricing decisions. Retailers using the Competera Pricing Platform report 3–7% revenue growth and a 2–5 percentage point margin improvement.
Competera's Adaptive AI models price elasticity to estimate demand at different price points, and Contextual AI adds the wider demand context across 20+ factors such as seasonality, promotions, and competitor moves. Retailers can use these estimates to compare the potential revenue associated with a pricing change, taking expected changes in volume into account rather than evaluating the new price on its own.
Pricing decisions can have effects beyond the SKU being changed. For example, a price adjustment on one product may influence demand for comparable products in the same category. Competera's Contextual AI incorporates these product relationships into portfolio pricing, allowing retailers to account for potential cross-product effects when managing dynamic pricing.
What-if simulations give pricing teams an opportunity to test potential changes before implementation. Competera forecasts volume, revenue, gross profit, and margin over 1–12 weeks, with probability ratings for each scenario, so retailers can compare the results before selecting an approach.
Knowing how to calculate marginal revenue gives you a way to measure how changes in sales affect total revenue. For retail pricing, it can be considered together with demand elasticity and cross-product effects. This allows retailers to assess pricing changes at the individual-product level and across the wider assortment.
Competera Pricing Platform applies demand elasticity modeling and cross-product margin analysis to generate price recommendations across the full assortment. Book a demo to see how it works on your categories.
The formula for marginal revenue is MR = ΔTR / ΔQ. If you want to know how to calculate marginal revenue, divide the change in total revenue by the change in the quantity sold.
Marginal revenue measures how total revenue changes when one more unit is sold. Average revenue describes the revenue associated with each unit when total revenue is spread across the quantity sold.
Calculating marginal revenue helps a business understand what an additional sale is worth in terms of total revenue. The result can inform decisions about sales volume and pricing.
Looking at marginal revenue together with marginal cost helps determine whether another unit is worth selling. Revenue above the additional cost can increase profit, while a higher marginal cost can make extra volume unprofitable. Profit is maximized where marginal revenue equals marginal cost.
For a business facing a downward-sloping demand curve, the marginal revenue curve sits below the demand curve, because selling more requires a lower price on every unit. How far below depends on the price elasticity of demand.
Retailers use marginal revenue to compare the expected change in sales with the resulting change in revenue before changing a price, with price elasticity showing how strongly demand will respond.