Joint Product Costing
Joint product costing refers to the process of accounting and allocating costs for a production process that yields multiple products simultaneously. Joint products are two or more products generated from a common input, and the costs associated with their production up to the split-off point are known as joint costs.
The split-off point is the stage in the production process at which joint products become separate and identifiable. After the split-off point, costs can be directly traced to each individual product. Before the split-off point, costs are considered joint because they can’t be directly assigned to one product or another.
Given that joint costs cannot be specifically attributed to individual products, they need to be allocated among the joint products in a rational and consistent manner. The goal of this allocation is to provide a basis for inventory valuation and cost control.
Several methods are commonly used to allocate joint costs to the joint products:
- Physical measure method: Allocating costs based on a physical attribute such as weight or volume. This method is simple but doesn’t consider the economic value of each product.
- Sales value at split-off method : Allocating costs based on each product’s relative sales value at the split-off point. This method considers the economic value of each product but may not always be applicable if products aren’t sold immediately at the split-off point.
- Net realizable value (NRV) method: Allocating costs based on each product’s expected sales value less any further costs required to make the product ready for sale. This method is often used when products require additional processing after the split-off point.
- Constant gross margin percentage NRV method: Allocating costs so that each product achieves the same gross margin percentage. This method is used when the company wishes to ensure a consistent profit margin across all products.
It’s important to remember that the method chosen for joint cost allocation can impact profitability analysis and pricing decisions, but these allocated costs may not accurately reflect the incremental cost or economic value of producing each product.
Example of Joint Product Costing
Let’s consider a petroleum refinery which processes crude oil to yield several products like gasoline, diesel, and lubricants.
Suppose the refinery incurs costs of $10 million to purchase and process the crude oil up to the split-off point, where it is separated into different products. Now these $10 million of joint costs need to be allocated to gasoline, diesel, and lubricants.
Let’s say the physical volume of the products at the split-off point is 40% gasoline, 40% diesel, and 20% lubricants.
- Physical Measure Method: The costs would be allocated based on their physical volume. Gasoline would be allocated 40% of the costs ($4 million), diesel also 40% ($4 million), and lubricants 20% ($2 million).
Suppose the sales values at the split-off point are $6 million for gasoline, $3 million for diesel, and $1 million for lubricants.
- Sales Value at Split-off Method: Costs would be allocated based on their relative sales values. Gasoline would be allocated 60% of the costs ($6 million), diesel 30% ($3 million), and lubricants 10% ($1 million).
Suppose that gasoline can be sold as is, but diesel and lubricants need further processing. After spending an additional $1 million, the diesel can be sold for $4.5 million, and the lubricants for $2 million.
- net realizable value (NRV) Method: Costs would be allocated based on the net realizable value of the products. Gasoline’s NRV is its sales value of $6 million, diesel’s NRV is its sales value of $4.5 million less further processing costs of $0.5 million ($4 million), and lubricants’ NRV is its sales value of $2 million less further processing costs of $0.5 million ($1.5 million). Thus, the joint costs would be allocated as follows: gasoline 46.15% ($4.615 million), diesel 30.77% ($3.077 million), and lubricants 23.08% ($2.308 million).
These examples illustrate how the choice of allocation method can significantly affect the cost assigned to each product.
