Cost-Volume-Profit Analysis

Summary :

This chapter explains cost behavior patterns and how to separate mixed costs into fixed and variable components using the scatter diagram and high-low method. It covers the relationship among costs, volume, revenue, and profits, finding the break-even point and margin of safety, applying cost-volume-profit analysis, and the assumptions and limitations that underlie it.

Cost behavior and separating mixed costs

Costs behave differently as volume changes: fixed costs stay constant in total regardless of activity level, while variable costs change in direct proportion to it, and many real costs are mixed, containing both a fixed and a variable element. The scatter diagram plots cost against activity to visualize this relationship, while the high-low method uses the highest and lowest activity levels observed to estimate the fixed and variable components mathematically.

Break-even point and margin of safety

The break-even point is the sales volume, in units or dollars, at which total revenue exactly equals total costs and profit is zero, found by relating the contribution margin, the amount each unit contributes toward fixed costs after covering its variable cost, to total fixed costs. The margin of safety measures how far actual or expected sales can fall before the company reaches that break-even point, giving managers a sense of how much cushion exists against a downturn.

Applying and questioning the analysis

Cost-volume-profit analysis can be applied to decisions such as setting sales targets for a desired profit or evaluating the effect of a change in price or cost structure, and computer spreadsheets make it practical to test many such scenarios quickly. The analysis rests on assumptions, including that costs and revenues behave in a straight-line manner within a relevant range and that sales mix stays constant, and automation's tendency to convert variable costs into fixed costs is changing how these relationships play out in practice.