Irrelevant Cost A managerial accounting term that represents a cost, either positive or negative, that does not relate to a situation requiring management's decision. Investopedia Says: As with relevant costs, irrelevant costs may be irrelevant for some situations but relevant for others. Examples of irrelevant costs are fixed overheads, notional costs, sunk costs and book values. Related Terms: Book Value Fixed Cost Managerial Accounting Overhead Relevant Cost Sunk Cost Variable Cost |