In making payments for its resources, the firm incurs costs of production. In the short run, a time frame over which capital is fixed, the total cost of any given level of output can be broken into fixed cost and variable cost. On a per unit basis, these can be expressed as average fixed cost and average variable cost, which together sum to average total cost. Marginal cost refers to the extra cost of producing one additional unit. Obviously, these short-run costs reflect both the costs and the productivity of the inputs.

The applet contains productivity data - the physical relationship between inputs and output - for a hypothetical firm. Total product, the relationship between labour input and output, is graphed on the upper panel, while marginal and average product are graphed below. Clicking and dragging the Productivity Index slider to the right allows you to increase the productivity of labour by any amount up to 25 percent.

By clicking on the Production/Costs button, the applet toggles to the graphical portrayal of the firm's cost curves: Variable Cost, Fixed Cost, and Total Cost are in the upper graph, while the lower panel contains the corresponding Marginal and Average-Total-Cost curves. You can change the wage rate and fixed cost by clicking on the corresponding bold values below the tabular productivity data. In either the production or the cost mode, clicking Reset restores all values to their initial levels.