An expense that an entity incurs in relation to its ordinary operations. Operating expenses include all items that arise from operations such as equipment, inventory costs, marketing, salaries/ wages, rent, insurance costs, step costs, and R&D allocations, and so on.

An operating expense is an ongoing cost for running an entity. It may also relate to a certain product or line of business.

Operations expenses are also known as selling, general and administrative expenses (SG&A).

It is abbreviated as OpEx.