Opportunity cost

Opportunity cost is the value of the next-best alternative that is given up when a person, firm or public body chooses one course of action. It is not the sum of every option left unchosen: it refers to the best available alternative under the circumstances. Nor is it limited to a purchase price. Depending on the decision, the forgone alternative may involve money, time, output, use of an asset or another benefit. The concept makes the trade-offs behind choices explicit.

Individuals and households make choices with limited budgets and time. A budget constraint, for example, shows combinations of goods a consumer can afford; choosing more of one may leave less room for another. Economists describe the relevant cost as the value of what must be forgone, rather than only the money paid for the chosen item. In practice, that value can be personal and hard to measure, especially when the alternatives offer different kinds of benefits.

For firms, opportunity costs can include the value of resources already owned and used in production, even when no money changes hands. Economists distinguish explicit costs, such as wages or rent paid, from implicit costs, such as the alternative use of an owner's time or property. Accounting profit subtracts explicit costs from revenue; economic profit also accounts for implicit costs. This distinction helps show whether a business activity is worthwhile compared with the best alternative use of its resources.

The same reasoning applies when a society allocates limited resources among competing uses. A production possibilities frontier represents feasible combinations of two outputs; moving along it to produce more of one requires giving up some of the other. In that model, the slope indicates the opportunity cost of additional output. Because resources differ in how well they can be used for each purpose, the marginal opportunity cost may change as production shifts, rather than remaining fixed.

Opportunity-cost analysis is used to clarify trade-offs in consumer decisions, business planning, investment and public resource allocation. It is a way to organize comparison, not a rule that selects a universally correct choice: people and institutions may value outcomes differently. Estimates also depend on what the next-best alternative would have produced, which is often uncertain and may not have a clear monetary value. The concept is most useful when its assumptions and the alternatives being compared are made explicit.