固定費と変動費

Fixed costs are expenses that remain constant regardless of output level. Examples include supervisor salaries, equipment maintenance, and factory rent. Firms must pay these costs even if they produce nothing because they represent ongoing obligations tied to capital inputs and permanent labor contracts that cannot be avoided without closing the business entirely.

Variable costs fluctuate directly with production output, including worker wages and material expenses like fabric and buttons. Unlike fixed costs, variable costs equal zero when production stops. A shirt manufacturer incurs higher variable costs as output increases, but these expenses scale with production volume rather than remaining constant.

Firms stay open if revenues cover all variable costs and contribute toward fixed cost obligations. Since fixed costs are sunk and unavoidable in the short run, the firm minimizes losses by operating rather than shutting down. This strategy applies as long as revenue exceeds variable costs, making continued operation more profitable than closure.

Variable costs are the only production expenses that influence short-run output decisions. Since fixed costs are sunk and cannot be recovered, firms focus on whether variable costs can be covered by revenue. This determines how much output to produce and whether staying in business remains economically rational.

Yes, labor expenses can be fixed costs if workers are permanent staff with contracts requiring payment regardless of production levels. Supervisor salaries exemplify fixed labor costs. In contrast, daily worker wages are variable costs because they fluctuate with production output and cease when production stops.

Variable costs become zero when production stops completely. Since these costs directly correlate with output volume, eliminating production eliminates all variable expenses. This differs from fixed costs, which persist regardless of production level and must be paid even during complete production shutdowns.

Fixed costs are sunk because they cannot be recovered or avoided in the short run, regardless of production decisions. Whether a firm produces or shuts down temporarily, these obligations persist. This irreversibility means fixed costs should not influence short-run output decisions; only variable costs matter for determining production levels.