Absorption costing, also known as full costing, is a costing method in managerial accounting that allocates all manufacturing costs, both fixed and variable, to the cost of a product. This differs from variable costing, which only assigns variable costs to products. Under absorption costing, the total cost of a product includes direct materials, direct labor, variable overhead, and fixed overhead.
The primary benefit of absorption costing is that it provides a more complete picture of the cost of producing a product. It is required for external financial reporting under Generally Accepted Accounting Principles (GAAP) and International Financial Reporting Standards (IFRS). This is because it includes all manufacturing costs, reflecting the true economic cost of production. This comprehensive cost helps in setting realistic selling prices that cover all production expenses and contribute to profit margins.
The core principle of absorption costing is to allocate fixed manufacturing overhead to each unit produced. This allocation is typically based on a predetermined overhead rate. The formula for calculating this rate is: Predetermined Overhead Rate = Estimated Total Fixed Overhead Costs / Estimated Total Allocation Base
. The allocation base can be machine hours, direct labor hours, or any other measure that has a causal relationship with overhead costs. Once the rate is determined, it is applied to each unit produced. For example, if the predetermined overhead rate is $10 per machine hour and a product requires 2 machine hours, $20 of fixed overhead would be allocated to that product.
However, absorption costing can lead to significant differences in reported income between periods, particularly when production volume and sales volume differ. If production exceeds sales, ending inventory will increase, and some of the fixed overhead costs will be deferred to future periods as part of the inventory value. This results in a higher net income under absorption costing compared to variable costing, because not all of the fixed overhead is expensed in the current period.
Conversely, if sales exceed production, ending inventory will decrease, and fixed overhead costs that were previously deferred in inventory will be released and expensed. This will lead to a lower net income under absorption costing than under variable costing. This fluctuation in reported income can make it difficult to assess the true profitability of a company and can potentially lead to managerial decisions based on misleading information.
While absorption costing is required for external reporting, companies often use variable costing for internal decision-making. Variable costing provides a clearer picture of the incremental costs associated with producing each unit, which can be helpful for pricing decisions, break-even analysis, and cost-volume-profit (CVP) analysis. Understanding both absorption and variable costing methods allows managers to make more informed decisions and effectively manage their company’s financial performance.