Break-even analysis, also known as break-even point analysis or cost-volume-profit analysis, is a mathematical analysis method to predict profits, control costs and judge operating conditions according to the comprehensive analysis of the mutual restriction between product business volume (output or sales volume), cost and profit. Generally speaking, enterprise income = cost+profit. If the profit is zero, there is income = cost = fixed cost+variable cost, while income = sales volume × price, variable cost = unit variable cost × sales volume. Therefore, from sales volume × price = fixed cost+unit variable cost × sales volume, the calculation formula of breakeven point can be deduced as follows: breakeven point (sales volume) = fixed cost Ⅱ.

Corporate profit is the balance of sales revenue after deducting costs. Sales revenue is the product of product sales and sales unit price. Product costs include factory costs and sales expenses, which are divided into fixed costs and variable costs.