variable costs

Variable costs are expenses that change in proportion to the activity of a business. In other words, variable cost is the sum of marginal costs. Along with fixed costs, variable costs make up the two components of total cost. Direct Costs, however, are costs that can be associated with a particular cost object. Not all variable costs are direct costs, however; for example, variable manufacturing overhead costs are variable costs that are not a direct costs, but indirect costs.Variable costs are sometimes called unit-level costs as they vary with the number of units produced.
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costs that vary directly with the volume or quantity produced; variable costs plus fixed costs equal total costs. See Fixed Costs; Total Costs.

cost that vary directly with output (see fixed costs).

a unit cost which depends on total volume.Cost/Benefit Analysis A technique designed to determine the feasibility of a project or plan, by quantifying its costs and benefits.