| Measurement | Definition | Mathematical term |
| Short run | Fixed cost | Cost that does not depend on the quantity of output produced | FC |
| Average fixed cost | Fixed cost per unit of output | AFC = FC/Q |
| Short run and long run | Variable cost | Cost that depends on the quantity of output produced | VC |
| Average variable cost | Variable cost per unit of output | AVC = VC/Q |
| Total cost | The sum of fixed cost (short run) and variable cost | TC = FC (short run) + VC |
| Average total cost (average cost) | Total cost per unit of output | ATC = TC/Q |
| Marginal cost | The change in total cost generated by producing one more unit of output | MC = ΔTC/ΔQ |
| Long run | Long-run average total cost | Average total cost when fixed cost has been chosen to minimize average total cost for each level of output | LRATC |