Joint and By-Products Costing: Practical Illustrations and Examples

Joint and by-products costing can feel like solving a puzzle where you need to fairly distribute shared costs among multiple products that emerge from the same production process. Whether it’s a petroleum refinery producing gasoline, diesel, and heating oil from crude oil, or a dairy processing milk into cheese, butter, and whey, businesses constantly face the challenge of accurately allocating costs to determine profitability and make informed pricing decisions.

Understanding joint and by-products through real scenarios 🔗

Before diving into the costing methods, let’s establish what we’re working with. Joint products are multiple products of significant commercial value that are produced simultaneously from the same raw material or production process. Think of a sawmill that processes logs into lumber, wood chips, and sawdust – all valuable products from the same input.

By-products, on the other hand, are secondary products with relatively minor commercial value compared to the main product. Using our sawmill example, if the primary focus is lumber production, then wood chips and sawdust would be considered by-products. The key distinction lies in their relative importance and value to the business.

The split-off point concept 🔗

The split-off point is crucial in joint costing – it’s the stage in production where individual products can be identified and separated. Up to this point, all costs are considered joint costs because they benefit all products equally. After the split-off point, any additional processing costs can be directly attributed to specific products.

Market value method: The most popular approach 🔗

The market value method allocates joint costs based on the relative sales values of the joint products at the split-off point. This method assumes that products with higher market values should bear a proportionally higher share of joint costs.

Let’s work through a practical example. Imagine a chemical company that processes 1,000 kg of raw material costing $50,000 into three products:

• Product A: 400 kg with a market value of $60 per kg
• Product B: 300 kg with a market value of $80 per kg
• Product C: 200 kg with a market value of $100 per kg

First, we calculate the total market value: (400 × $60) + (300 × $80) + (200 × $100) = $24,000 + $24,000 + $20,000 = $68,000

Next, we determine each product’s share of joint costs:

• Product A: ($24,000 ÷ $68,000) × $50,000 = $17,647
• Product B: ($24,000 ÷ $68,000) × $50,000 = $17,647
• Product C: ($20,000 ÷ $68,000) × $50,000 = $14,706

This method is widely preferred because it aligns cost allocation with revenue-generating capacity, making it logical for decision-making purposes.

Physical units method: When market values aren’t available 🔗

Sometimes, market values at the split-off point aren’t readily available or reliable. In such cases, the physical units method allocates joint costs based on measurable physical characteristics like weight, volume, or quantity.

Using our chemical company example, if we only knew the quantities produced:

• Total production: 900 kg (400 + 300 + 200)
• Product A allocation: (400 ÷ 900) × $50,000 = $22,222
• Product B allocation: (300 ÷ 900) × $50,000 = $16,667
• Product C allocation: (200 ÷ 900) × $50,000 = $11,111

While this method is simple and objective, it may not reflect the economic reality of different products’ values and profitability.

Reverse cost method: Working backwards from profitability 🔗

The reverse cost method, also known as the net realizable value method, is particularly useful when products require further processing after the split-off point. This method works backwards from the final selling price, deducting separable costs and a normal profit margin to determine how much joint cost each product should bear.

Consider a timber company that processes logs into rough lumber at a joint cost of $100,000. The rough lumber then undergoes different finishing processes:

• Premium lumber: 2,000 units requiring $20,000 additional processing, selling for $80 per unit
• Standard lumber: 3,000 units requiring $15,000 additional processing, selling for $45 per unit

First, we calculate the net realizable value for each product:

• Premium lumber: (2,000 × $80) – $20,000 = $140,000
• Standard lumber: (3,000 × $45) – $15,000 = $120,000
• Total net realizable value: $260,000

Then we allocate joint costs based on these values:

• Premium lumber: ($140,000 ÷ $260,000) × $100,000 = $53,846
• Standard lumber: ($120,000 ÷ $260,000) × $100,000 = $46,154

By-product costing: Maximizing value from secondary outputs 🔗

By-product costing requires a different approach since these products aren’t the primary focus of the production process. The goal is to account for any value they generate while keeping the accounting treatment simple.

Revenue recognition methods 🔗

The most common approach is to treat by-product revenue as a reduction in the cost of the main product. For example, if a furniture manufacturer’s primary product is tables, but the process also produces wood shavings sold for $2,000, this amount would reduce the total cost allocated to table production.

Another approach is the cost allocation method, where by-products receive a small allocation of joint costs based on their relative importance. This method is used when by-products have significant value or when more detailed cost tracking is required.

Further processing decisions 🔗

Sometimes by-products can be processed further to increase their value. The decision to undertake additional processing should be based on whether the incremental revenue exceeds the incremental costs.

Consider a dairy that produces cheese as its main product and whey as a by-product. The whey can be sold as-is for $0.50 per kg or processed into protein powder for $3.00 per kg, with additional processing costs of $1.80 per kg. The incremental analysis shows: Additional revenue ($3.00 – $0.50 = $2.50) exceeds additional costs ($1.80), so further processing is profitable.

Practical challenges and solutions 🔗

Real-world joint costing presents several challenges that textbook examples often overlook. Market prices fluctuate, making the market value method less stable over time. Production yields vary, affecting the reliability of physical unit allocations. Additionally, the classification of products as joint products versus by-products can change based on market conditions.

To address these challenges, many companies use a combination of methods or adjust their approaches based on specific circumstances. Some adopt the market value method for external reporting while using physical units for internal decision-making, recognizing that different purposes may require different allocation methods.

Strategic implications for business decisions 🔗

The choice of costing method significantly impacts reported product profitability, which in turn influences strategic decisions about pricing, product mix, and resource allocation. Understanding these implications helps managers make better decisions about which products to emphasize, how to price them competitively, and when to discontinue unprofitable lines.

For instance, if the market value method shows that a particular joint product is barely profitable, management might explore ways to increase its market value through improved processing or marketing, rather than simply accepting low profitability.

What do you think? How might a company’s choice of joint cost allocation method affect its pricing strategy and competitive position? Can you identify situations where switching from one method to another might be beneficial for a business?