Marginal Revenue Calculator
Use two output/revenue points to calculate marginal revenue (MR).
What is marginal revenue?
Marginal revenue is the additional revenue a business earns by selling one more unit of output. In plain terms, it answers this question: “If I increase sales a little bit, how much extra money comes in?”
This concept is central in economics, accounting, pricing strategy, and profit maximization. Businesses compare marginal revenue to marginal cost to decide whether producing and selling additional units is worth it.
Formula to calculate marginal revenue
The standard discrete formula is:
MR = ΔTR / ΔQ = (TR2 − TR1) / (Q2 − Q1)
- MR = Marginal Revenue
- TR = Total Revenue
- Q = Quantity sold
- Δ = Change in a value
If you are in a calculus-based setting, marginal revenue can also be expressed as the derivative of total revenue with respect to quantity: MR = d(TR)/dQ.
How to calculate it step by step
Step 1: Find two quantity levels
Pick two output points, such as 100 units and 110 units.
Step 2: Find total revenue at each point
Example: at 100 units, TR is $5,000; at 110 units, TR is $5,400.
Step 3: Compute changes
ΔTR = 5,400 − 5,000 = 400 and ΔQ = 110 − 100 = 10.
Step 4: Divide
MR = 400 / 10 = 40. This means each additional unit in that range brings in an average of $40 in additional revenue.
Quick interpretation guide
- Positive MR: Selling more increases total revenue.
- Zero MR: Additional units are not increasing revenue.
- Negative MR: Additional units reduce total revenue (often due to steep price cuts).
Marginal revenue and demand curve behavior
In perfectly competitive markets, firms are price takers, so marginal revenue is often equal to market price. Under imperfect competition (like monopoly or differentiated products), selling one more unit may require lowering price, so marginal revenue is usually less than price.
That is why understanding your demand curve, price elasticity, and revenue response matters so much in real-world pricing decisions.
Marginal revenue vs. marginal cost
The classic profit rule is straightforward:
- If MR > MC, producing one more unit can increase profit.
- If MR < MC, producing one more unit can reduce profit.
- Profit is often maximized near the point where MR = MC.
This is one of the most important decision rules in managerial economics.
Common mistakes when using the formula
- Using price instead of total revenue: MR uses change in total revenue, not just unit price.
- Forgetting quantity change: If Q₂ = Q₁, the formula is undefined (division by zero).
- Mixing time periods: Compare data from consistent periods and conditions.
- Ignoring discounts: Promotional pricing can lower MR faster than expected.
Practical business applications
You can use the marginal revenue formula in:
- Pricing experiments (A/B tests for price points)
- Sales forecasting and revenue planning
- Inventory and production decisions
- Subscription and SaaS tier optimization
- E-commerce promotion analysis
Even a simple spreadsheet with quantity and total revenue columns can reveal useful marginal trends over time.
Final takeaway
The formula to calculate marginal revenue is simple, but the insight is powerful. Track how total revenue changes with output, calculate MR regularly, and combine it with marginal cost to make better decisions about pricing, production, and growth.