In a perfectly competitive market, an industry or firm will maximize its profit when its Marginal Cost (MC) equals Marginal Revenue (MR). This is a fundamental principle of microeconomics that ensures the firm's resources are being used most efficiently.
Here's why:
- Marginal Cost (MC) is the additional cost incurred from producing one more unit of a good or service.
- Marginal Revenue (MR) is the additional revenue generated from selling one more unit of a good or service.
If MC = MR, the cost of producing an additional unit is exactly equal to the revenue it generates, meaning any increase or decrease in production would not improve profitability. At this point, the firm is efficiently allocating its resources.
If MC < MR; it means that the cost of producing an extra unit is less than the revenue it brings. The firm can increase its profit by producing and selling more units.
Conversely, if MC > MR; the cost of producing an extra unit exceeds the revenue it brings, and the firm should reduce production to avoid losses.
Therefore, to achieve maximum profit, a firm in a perfectly competitive market should continue adjusting its output until the cost of the last unit produced is exactly equal to the revenue it produces, which occurs at MC = MR.