Welcome to Management Accounting: Mastering Product Costs!
Ever wondered how a company like Apple decides the price of an iPhone, or how a local bakery knows if they are actually making money on each croissant? It’s not just about the ingredients or the screen; it’s about the "hidden costs" like electricity, rent, and management salaries.
In this chapter, we are exploring Absorption Costing and Activity Based Costing (ABC). These are two different ways to "soak up" those hidden costs into the price of a product. Don't worry if this seems tricky at first—once you see the logic behind the numbers, it all starts to click!
1. Absorption Costing: The Traditional Way
Absorption Costing aims to include all manufacturing costs in the cost of a product. We "absorb" both Direct Costs (like raw materials) and Indirect Costs (overheads like factory rent) into the final product cost.
Key Terminology
Before we crunch numbers, let's learn the language:
Allocation: This is simple! If a cost belongs 100% to one specific department (like the salary of the manager of the "Assembly Room"), we allocate it directly there.
Apportionment: This is for shared costs. If the whole factory pays one electricity bill, we have to "split" it between departments using a fair basis (like floor space or number of machines).
Absorption: This is the final step where we "charge" the overheads to the actual products being made.
How to Calculate the Total Cost (Step-by-Step)
Step 1: Identify Direct Costs
Add up Direct Materials, Direct Labour, and Direct Expenses. These are easy to trace to a single product.
Step 2: Apportion Indirect Costs (Overheads)
We share out the general factory costs.
Analogy: Think of splitting a pizza bill. If one person ate 4 slices and another ate 2, you wouldn't split it 50/50. You’d split it based on how much they ate! In accounting, we split rent based on "Floor Area" and power based on "Machine Hours."
Step 3: Calculate the Overhead Absorption Rate (OAR)
We need a formula to decide how much overhead each product gets. The most common way is based on time (Labour Hours or Machine Hours).
\( \text{OAR} = \frac{\text{Budgeted Overheads}}{\text{Budgeted Activity Level (e.g., hours)}} \)
Step 4: The Final Calculation
Total Product Cost = Direct Costs + (Actual Hours worked on the product \(\times\) OAR)
Under and Over Absorption
Because the OAR is usually calculated at the start of the year using estimates (budgets), the amount we "absorb" might be different from what we actually spend.
Over-absorption: We charged more to products than we actually spent (Profit looks higher!).
Under-absorption: We didn't charge enough, so we have "hidden" costs left over (Profit looks lower!).
Quick Review: Absorption costing ensures all factory costs are covered by the product's price. It follows the Matching Principle (Accruals concept) because it matches all costs of production against the revenue from sales.
2. Activity Based Costing (ABC): The Modern Way
Traditional absorption costing can be a bit "clumsy." It assumes that if a product takes a long time to make, it must cause all the overheads. But what if a product is quick to make but requires 50 quality checks?
Activity Based Costing (ABC) is a more precise method. It looks at the specific activities that cause costs.
Key Terminology
Cost Pool: A "bucket" where we collect all costs related to a specific activity (e.g., "Machine Setup Costs" or "Quality Inspection Costs").
Cost Driver: The thing that makes the cost go up or down (e.g., the number of setups or the number of inspections).
Attribution: The process of linking the cost to the product using the driver.
How ABC Works
Instead of one big factory OAR, we calculate an OAR for every activity.
Example:
If the "Quality Control" cost pool is £10,000 and we perform 500 inspections (the driver):
\( \text{ABC Rate} = \frac{£10,000}{500 \text{ inspections}} = £20 \text{ per inspection} \)
If Product A needs 2 inspections, we add £40 to its cost. If Product B needs 0 inspections, it pays £0 for that activity. Much fairer!
Did you know? ABC is very popular in modern manufacturing where robots do most of the work. In these factories, "Labour Hours" aren't a good way to measure costs anymore!
3. Calculating Selling Price
Both methods are used to help businesses set their Selling Price. Usually, businesses use Cost-Plus Pricing.
The Formula:
\( \text{Selling Price} = \text{Total Product Cost} + \text{Target Profit (Mark-up)} \)
If you use ABC, your price will be more accurate for complex products. If you use traditional Absorption, you might accidentally under-price difficult products and over-price simple ones.
4. Comparison: Absorption vs. ABC vs. Marginal Costing
Students often find the choice between these three confusing. Here is a simple breakdown:
Absorption Costing
Benefits: Recognizes that all costs must be covered; accepted for financial statements; easy to calculate.
Limitations: Can be inaccurate; encourages over-production to "hide" overheads in inventory.
Activity Based Costing (ABC)
Benefits: Very accurate for complex businesses; helps managers see which activities are too expensive; better for setting competitive prices.
Limitations: Time-consuming and expensive to set up; can be difficult to pick the right "drivers."
Marginal Costing
Note: Unlike the other two, Marginal Costing only looks at variable costs (like materials). It ignores fixed overheads when calculating product cost.
Key Difference: In Absorption/ABC, fixed overheads are included in inventory value. In Marginal, they are treated as expenses for the period. This means Profit can be different between the methods if inventory levels change!
Memory Aid: "A" for All
Remember: Absorption costing includes All manufacturing costs (Fixed + Variable). Marginal costing Misses out the fixed costs from the product cost.
Common Mistakes to Avoid
1. Don't mix up the bases: In Absorption, don't use Machine Hours if the question says the factory is "Labour Intensive."
2. Math Error: When calculating OAR, it is always Money divided by Activity (e.g. \( \frac{£}{\text{Hours}} \)). If you do it the other way around, your answer will be upside down!
3. Ignoring Direct Costs: When a question asks for "Total Product Cost," always start by adding the Direct Materials and Labour before you even look at the overheads.
Key Takeaways for your Revision
- Absorption Costing: Uses Allocation, Apportionment, and one or two OARs to spread overheads.
- ABC: Uses Cost Pools and Cost Drivers for more accuracy. Better for modern, complex businesses.
- OAR Formula: \( \frac{\text{Budgeted Overheads}}{\text{Budgeted Activity}} \).
- Profit Impact: If inventory increases, Absorption Costing will usually show a higher profit than Marginal Costing because some fixed costs are "stored" in the unsold stock.
Don't worry if the calculations take a few tries to get right. Management accounting is all about practice! Keep looking at the logic: we are just trying to find the fairest way to share out the bills.