Total costs and unit costs Students often treat unitised fixed costs as if they were variable costs, forgetting that fixed costs are fixed in total. They attempt to calculate total costs by multiplying the cost per unit by the number of units. Because of this misleading nature of unitised fixed costs, it is better to base projections and comparisons on total costs. When estimating total costs, students should consider variable costs as an amount per unit and fixed costs as a lump sum total amount.
