marginalinntekt

Marginalinntekt is a term used in Swedish economics to describe the change in total income that results from selling one additional unit of a good or service. In English-language texts, this concept is usually called marginal revenue. The idea focuses on the revenue side of a firm’s decision about how much to produce.

In a perfectly competitive market, marginalinntekt equals the market price, because selling one more unit raises revenue by the fixed price. In markets with downward-sloping demand, marginalinntekt is generally less than the price and declines as output increases. This occurs because to sell more units, a firm must lower the price on all units sold, not just the additional unit.

Mathematically, if total revenue TR(Q) is a function of quantity Q, then marginalinntekt is the derivative MR = dTR/dQ. For a linear demand curve P = a − bQ, total revenue is TR = aQ − bQ^2, and marginalinntekt is MR = a − 2bQ. This shows how MR falls as output expands.

Firms use marginalinntekt together with marginal cost (MC) to decide how much to produce. The profit-maximising quantity occurs where MR = MC. If MR > MC, increase output; if MR < MC, reduce output. Marginalinntekt is thus central to understanding price, output decisions, and competitive strategy.

Note that marginalinntekt is distinct from concepts like marginal propensity to consume, which relates to how changes in income affect consumption rather than revenue from production. See also marginal cost, marginal revenue, and profit maximisation.