Exhibit 13 shows an example of how total, average, and marginal costs are derived. Total costs are calculated by summing total fixed cost and total variable cost. Marginal cost is derived by taking the change in total costs as the quantity variable changes. Exhibit 14 graphically displays the data for total costs, total variable cost, and total fixed cost from the table in Exhibit 13.

Exhibit 13. Total, Average, Marginal, Fixed, and Variable Costs

Quantity (Q)	Total Fixed Costa(TFC)	Average Fixed Cost (AFC)	Total Variable Cost (TVC)	Average Variable Cost (AVC)	Total Costs (TC)	Average Total Cost (ATC)	Marginal Cost (MC)
0	100	—	0	—	100	—	—
1	100	100.0	50	50.0	150	150.0	50
2	100	50.0	75	37.5	175	87.5	25
3	100	33.3	125	41.7	225	75.0	50
4	100	25.0	210	52.5	310	77.5	85
5	100	20.0	300	60.0	400	80.0	90
6	100	16.7	450	75.0	550	91.7	150
7	100	14.3	650	92.9	750	107.1	200
8	100	12.5	900	112.5	1,000	125.0	250
9	100	11.1	1,200	133.3	1,300	144.4	300
10	100	10.0	1,550	155.0	1,650	165.0	350

^a Includes all opportunity costs.