📈 Marginal Revenue Calculator

Marginal revenue is what the next unit actually earns you: the change in total revenue divided by the change in quantity sold. Moving from 1,000 units at $80,000 revenue to 1,200 units at $93,000 means the 200 extra units brought $13,000, or $65 each. This calculator finds that number from any two sales levels and sets it against the average price.

The figure disciplines every volume decision. Revenue growth flatters; marginal revenue interrogates. A company can post record sales while each additional unit earns less and less, and only the marginal number reveals when growth turns self-defeating.

How to Use This Calculator

Enter two sales levels with their realized total revenues. The calculator returns marginal revenue per unit plus the average price at the higher level.

The Formula

Use realized revenue, not list price times quantity. Discounts, rebates, and mix shifts live in the realized number, and they are usually the reason marginal revenue trails the sticker price. A calculation from list prices measures a fantasy; from realized revenue it measures the business.

Marginal Versus Average Revenue

The $12.50 gap is the price of growth: to move 200 more units, the effective price fell. That erosion is normal and often worth it, but it must be measured against marginal cost. If marginal cost is $40, the $65 marginal revenue still earns $25 per unit and expansion pays. If marginal cost were $70, every extra unit would lose $5. For the pricing-power interpretation, our Lerner Index calculator translates the gap into market power.

Worked Example

With the defaults: quantity rises from 1,000 to 1,200, a change of 200 units. Revenue rises from $80,000 to $93,000, a change of $13,000. Marginal revenue is 13,000 / 200 = $65.00 per unit. Average revenue at 1,200 units is 93,000 / 1,200 = $77.50. Against a $40 marginal cost, each additional unit contributes $25 of profit, so expanding output from 1,000 toward 1,200 was profitable on every unit.

Using It Well

Apply the MR-equals-MC rule literally: keep expanding while marginal revenue tops marginal cost, stop where they meet. Recompute after every price change, because the curve moves with you. And watch for negative marginal revenue in heavy promotional periods; it means the discounting has gone past the point of revenue sense, let alone profit.

My rule: report marginal revenue alongside total revenue in every sales review. Totals tell you where you have been; the marginal number tells you whether the next step forward is uphill or off a cliff.

Marginal Revenue and Market Structure

Marginal revenue behaves differently depending on competition. A wheat farmer takes the market price, so marginal revenue equals price on every bushel: the demand curve is flat. A monopolist faces the whole downward-sloping demand curve, so each extra unit forces a price cut on all units, making marginal revenue fall faster than price. Most real businesses sit between, with some pricing power that erodes as volume grows.

This is why the profit rule is marginal revenue equals marginal cost, not price equals marginal cost. Produce while the next unit adds more revenue than cost; stop when it does not. In practice, firms estimate marginal revenue from price tests, promotions, or A/B tests on their own demand curve, then compare against the marginal cost of fulfillment. The two calculators together give you the complete incremental-profit picture. For pricing power context, our Lerner index calculator measures how far price sits above marginal cost.

Estimating Your Demand Curve

You cannot compute marginal revenue without knowing how price affects quantity, so the real work is estimating demand. The cheapest method is structured price testing: vary prices across comparable stores, time periods, or customer cohorts and measure the quantity response. Promotions are natural experiments if you track the baseline carefully. For digital products, A/B tests on pricing pages give clean reads within weeks.

Watch for confounders: seasonality, competitor moves, and marketing spend all shift demand independently of price. Regression analysis that controls for these beats naive before-and-after comparisons. Once you have the curve, marginal revenue at each quantity follows, and the profit-maximizing point is where it meets marginal cost. Revisit the estimate yearly; demand curves drift as markets mature and alternatives appear.

One more subtlety: marginal revenue can go negative. When demand is inelastic, cutting price to sell more actually reduces total revenue, because the price drop on existing units outweighs the new volume. This is the mathematical reason luxury brands destroy unsold inventory rather than discount it.