Why marginal revenue matters
Marginal revenue tells you whether the next unit of output is worth producing. Pair it with marginal cost: a firm maximizes profit at the quantity where MR = MC. Above that point, each unit loses money; below it, you're leaving profit on the table.
- • MR > MC → expand output.
- • MR < MC → cut output.
- • MR = MC → profit-maximizing quantity.
Marginal revenue vs price
Under perfect competition (commodity markets, frictionless price-takers), MR equals the market price. Under any pricing power — brands, network effects, switching costs — MR is less than price because adding volume usually requires lowering the price for ALL units, not just the new one.
Marginal revenue — the revenue earned from selling one additional unit — drives every real pricing decision: whether to discount, whether to expand production, whether a new channel is worth opening. Most operators conflate marginal with average revenue and end up over-discounting. This calculator separates the two and flags the unit count where MR drops below MC.
What each input means
Get these inputs right and the output is reliable. Get them wrong and the calculator just multiplies bad assumptions.
Current units sold
Quantity at the current price point.
Typical range: Use last 30/90-day actuals, not a single peak.
Current price
Effective price after discounts and promos.
Typical range: Use the net realized price, not list.
Price after the change
New price you're considering.
Typical range: Test 5%, 10%, 20% moves in either direction.
Expected units at new price
Forecast using historical elasticity if available.
Typical range: Assume −1.0 to −2.5 elasticity for consumer goods; −0.3 to −0.8 for sticky subscription products.
Worked examples
Real scenarios with the math walked through line by line.
Price increase test
Scenario: Currently selling 1,000 units at $40. Test $45 with forecast 880 units.
Math: Old revenue = $40,000. New revenue = $39,600. Δrev = −$400 over −120 units. Marginal revenue per lost unit = +$3.33.
Outcome: Revenue nearly flat but margin per remaining unit improved. Strong move if variable cost is significant.
Discount that doesn't pay back
Scenario: Drop $50 to $40 (20% off); units rise from 500 to 650.
Math: Old rev = $25,000. New = $26,000. ΔR = +$1,000 / +150 units. MR ≈ $6.67 per added unit.
Outcome: If variable cost per unit > $6.67, the promo loses money. Run the unit economics before approving any discount.
Common mistakes
Where this calculation usually goes wrong in the real world.
- Using average revenue (price) as marginal revenue. AR ≠ MR whenever demand isn't perfectly elastic.
- Forgetting the discount applies to everyone, not just the marginal buyer.
- Ignoring marginal cost in the same step — MR alone doesn't decide.
- Assuming constant elasticity. Demand curves bend; small-sample elasticity rarely projects to large price moves.
When to use this calculator
- Pricing experiments and promo decisions.
- Capacity expansion (does the next batch pay for itself?).
- Bundling decisions (does pulling out one SKU lift the bundle's marginal revenue?).
- Channel evaluation (is the marketplace's marginal revenue, net of take rate, above MC?).
Glossary
Marginal revenue (MR)
Change in total revenue from selling one additional unit. ΔRevenue ÷ ΔQuantity.
Price elasticity
% change in quantity ÷ % change in price. Elastic (|ε|>1): revenue rises with discount. Inelastic (<1): revenue rises with price increase.
Marginal cost (MC)
Variable cost of producing one additional unit. Profit-maximizing volume is where MR = MC.
More questions answered
How is marginal revenue different from gross revenue?
Gross revenue is total sales; marginal revenue is what changes when you sell one more unit. In a flat-pricing world they look similar, but the moment you introduce promos, tiered pricing, or volume discounts, marginal revenue can be a fraction of the headline price — sometimes negative if the discount cannibalizes existing buyers.
When is negative marginal revenue possible?
When a discount on incremental units forces a price cut on existing customers too. Example: dropping list price from $50 to $40 to attract 100 more buyers reduces revenue from your existing 500 buyers by $5,000 — so MR per added unit is −$10 even though gross revenue rose. Tiered pricing and volume discounts avoid this.
How do I estimate elasticity for my product?
Cleanest source: historical price experiments. Failing that, look up category benchmarks (consumer staples −0.3 to −0.7; luxury goods −1.5 to −3; SaaS −0.5 to −1.2). For a quick read, run a 7-day A/B at ±10% price on a meaningful traffic slice; if conversion barely moves, elasticity is sub-unitary and you can likely raise price.
Related guides
Long-form playbooks on the same topic, written by the RevenueLab editorial team.
Marginal Revenue Explained 2026: MR, MC, Elasticity, and the Profit-Max Quantity
Why MR ≠ price, the linear-demand shortcut (MR slopes 2× faster), the elasticity formula MR = P(1+1/ε), and applying MR=MC to SaaS pricing.
Read the guideAmazon FBA Fees Explained: A Sellers' Guide to Real Unit Economics in 2026
Referral fees, FBA fulfillment, storage, returns, and ad spend — the line items that turn a 'profitable' Amazon SKU into a money loser, and how to model them honestly.
Read the guideData Study: How the YouTube Shorts Revenue Pool Actually Pays in 2026
A from-the-ground-up breakdown of the Shorts ad-pool math — what creators are actually clearing per million Shorts views by niche and country, why the spread is 10×, and where Shorts fit in a serious channel P&L.
Read the guideMethodology last reviewed: 2026-05 by the RevenueLab editorial team.
FAQ
How do I calculate marginal revenue?
MR = change in total revenue ÷ change in quantity. Use this calculator's two-point form: compare your starting (P₁, Q₁) to your post-change (P₂, Q₂).
Why is marginal revenue less than price?
Because lowering the price to sell one more unit usually means lowering the price across all units (not just the new one). The 'lost' revenue on inframarginal units offsets the new sale.
What's a negative marginal revenue?
It means a price cut hurt total revenue more than added volume helped. You're in the inelastic part of the demand curve — raise prices, don't cut.
How this calculator is built
Independently maintained
Written by Sam Doshi and the RevenueLab editorial team. We don't sell the data feeds this tool is built on.
Sourced from primary data
Benchmarks come from public AdSense / Stripe / IRS disclosures and reader-submitted data — never third-party "$X per view" claims. Full methodology.
Last reviewed
June 2026. We re-check every figure on the platform on a rolling quarterly cycle.
Editorial standards
See our editorial policy and disclaimer. Results are estimates, not advice.