In accounting and economics, a semi-variable cost (also referred to as semi-fixed cost) is an expense which contains both a fixed-cost component and a variable-cost component. It is often used to project financial performance at different scales of production. It is related to the scale of production within the business where there is a fixed cost which remains constant across all scales of production while the variable cost increases proportionally to production levels.

Using a factory as an example, fixed costs can include the leasing of the factory building and insurance, while the variable costs include overtime pay and the purchase price of the raw materials.