变动成本法和全部成本法是两种不同的成本计算方法。由于这两种方法对固定成本的处理方式不同,因而计算出来的税前净利也往往不等。只有在个别特定的条件下,两种方法计算的净利才会相等。目前国内外一些书刊的有关论述中,对这两种方法计算的净利,主要从两个方面进行比较:一是假定各期的产量不变,销售量可以变动;二是假定各期的销售量不变,而产量可以变动。通过实例分析,大多得出了如下结论:(1)当生产量和销售量相等时,两种方 Variable cost method and total cost method are two different methods of cost calculation. Because these two methods deal with fixed costs differently, the pre-tax net profit calculated is often not equal. Only under certain specific conditions, the net profit calculated by the two methods will be equal. In the current domestic and foreign publications, the net profit calculated by these two methods is mainly compared from two aspects: first, assuming that the output of each period remains unchanged, the sales volume can change; and secondly, the sales volume of each period is assumed. No change, but output can change. Through the example analysis, most of the following conclusions are drawn: (1) When the production volume and sales volume are equal, both parties