两者都属于成本计算方法。

Absorption costing指完全成本法。

完全成本法亦称“全部成本法”、‘归纳成本法”或“吸收成本法”。完全成本法就是在计算产品成本和存货成本时，把一定期间内在生产过程中所消耗的直接材料、直接人工、变动制造费用和固定制造费用的全部成本都归纳到产品成本和存货成本中去。由于完全成本法是将所有的制造成本，不论是固定的还是变动的，都吸收到单位产品上，所以这种方法也称为“归纳（或吸收）成本法”。在完全成本法下，单位产品成本受产量的直接影响，产量越大，单位产品成本越低，能刺激企业提高产品生产的积极性。但该法不利于成本管理和企业的短期决策。Absorption costing, sometimes called “full costing,” is a managerial accounting method for capturing all costs associated with manufacturing a particular product. All direct and indirect costs, such as direct materials, direct labor, rent, and insurance, are accounted for when using this method.

采用完全成本法的原因是：虽然固定性制造费用只是同企业生产能力的形成有关，不与产品生产直接相联系，但它仍是产品最终形成所必不可少的，所以应当成为产品成本的组成部分。在完全成本法下，单位产品成本受产量的直接影响，产量越大，单位产品成本越低，这样就能刺激企业提高产品生产的积极性。但是采用完全成本法计算出来的单位产品成本不仅不能反映生产部门的真实业绩，反而会掩盖或夸大它们的生产实绩；在产销量不平衡的情况下，采用完全成本法计算确定的当期税前利润，往往不能真实反映企业当期实际发生的费用，从而会促使企业片面追求高产量，进行盲目生产；另外采用这种方法不便于管理者进行预测分析、参与决策以及编制弹性预算等。

Variable costing指可变成本法。

它只计算提供服务时会直接影响生产过程的成本，而不计算固定成本。Variable costing is a concept used in managerial and cost accounting in which the fixed manufacturing overhead is excluded from the product-cost of production. The method contrasts with absorption costing, in which the fixed manufacturing overhead is allocated to products produced.

可变成本是指在总成本中随产量的变化而变动的成本项目，主要是原材料，燃料，动力等生产要素的价值;当一定期间的产量增大时，原材料，燃料，动力的消耗会按比例相应增多，所发生的成本也会按比例增大，故称为可变成本。可变成本等于总成本减固定成本。 

以下为相关双语示例，供参考：

Variable costing, on the other hand, only includes direct costs in the cost of a product. Indirect costs, or overhead expenses, are not included in the cost of the product under variable costing. Instead, they are treated as a period expense and are recorded in the income statement in the period in which they are incurred. Variable costing is typically used for management decision-making and planning purposes, as it provides a more accurate representation of the incremental costs associated with producing an additional unit of a product.

另一方面，可变成本仅包括产品成本中的直接成本。在可变成本法中，间接成本或间接费用并不属于产品的成本。相反，它们被视为期间开展，并于产生期间计入利润表。可变成本法通常用于管理决策和规划目的，因为其更准确地体现了与生产额外单位的产品有关的增量成本。

Due to the deepening of business management, absorption costing being adopted in current financial accounting don't satisfy the needs of the internal business management in some aspects.

随着企业管理的不断深化，现行财务会计采用的全部成本法在某些方面已不能适应企业内部管理的需要。