If we add the variable costs to the fixed costs against a given range of volume (so that the fixed costs remain completely fixed), and add in the sales revenue (which also increases in line with volume), we arrive at the break-even chart shown in Figure 3.5 overleaf. The sloping line that starts at O is the sales revenue. The total cost line starts at F, and represents the sum of fixed and variable costs. The point at which the sales revenue line crosses the total cost line is the break-even point. Below this point, a loss will be incurred; above it a profit will be made.
A helpful concept in evaluating break-even charts is that of contribution: