Process Costing – concepts, equivalent units, weighted‑average & FIFO, production report

1. What is Process Costing?

Process costing is a cost accumulation system used when identical or similar units are produced in a continuous flow (e.g., chemicals, textiles, food processing). Costs are recorded by department or process rather than by individual job.

Key characteristics:

2. Flow of Costs in a Process Costing System

Costs move from raw materials to WIP of each department, then to finished goods, and finally to COGS when sold.

3. Equivalent Units

When work‑in‑process (WIP) at period‑end is not 100 % complete, we express it in terms of equivalent units (EUs):

$$\text{EU}=\text{Physical units}\times \text{Percentage of completion}$$

Separate calculations are made for materials, labor, and overheads because their completion percentages may differ.

4. Methods of Computing Cost per Equivalent Unit

4.1 Weighted‑Average Method

All costs (opening WIP + current period) are averaged:

$$\text{Cost per EU}=\frac{\text{Opening WIP cost}+\text{Costs added during period}}{\text{Opening EU}+\text{Units started and completed}+\text{Closing EU}}$$

4.2 FIFO (First‑In‑First‑Out) Method

Only costs incurred during the period are allocated to units completed, while opening WIP is kept separate:

$$\text{Cost per EU}=\frac{\text{Costs added during period}}{\text{Units started and completed}+\text{Closing EU}}$$

The FIFO method provides a clearer picture of period‑specific performance.

5. Production Report

The production report summarizes the physical flow and cost flow for each department. A typical layout:

The report then shows cost per EU and cost allocation to units transferred out and closing WIP.

6. Journal Entries in Process Costing

6.1 When materials are issued to a department

6.2 When conversion costs (labor & overhead) are incurred

6.3 Transfer of completed units to next department

6.4 Transfer from last department to Finished Goods

6.5 Sale of finished goods

7. Reconciliation of Costs

The cost reconciliation ensures that the sum of costs accounted for in the production report equals the total costs incurred:

$$\text{Total costs to account for}=\text{Opening WIP cost}+\text{Costs added}=\text{Cost of units transferred out}+\text{Closing WIP cost}$$

8. Advantages & Disadvantages

9. Worked Numerical Example – “Mountain View Tea Processing Ltd.”

Background
Mountain View Tea Processing Ltd. (Kathmandu) produces black tea in a continuous flow. The plant has two main processes: Withering (Dept A) and Fermentation (Dept B). The following data are for the month of June.

9.1 Data for Dept A (Weighted‑Average)

9.2 Compute Equivalent Units (Dept A)

• Materials: All units (opening + started) are 100 % material‑complete.
  $$\text{EU Materials}=(2,000+18,000)=20,000\text{kg}$$

• Conversion (labour + OH):
  $$\text{EU Conversion}=\underset{\text{Opening}}{\underbrace{2,000\times 0.30}}+\underset{\text{Started and completed}}{\underbrace{18,000}}+\underset{\text{Closing}}{\underbrace{3,000\times 0.50}}=600+18,000+1,500=20,100\text{kg}$$

9.3 Cost per Equivalent Unit (Weighted‑Average)

9.4 Allocate Costs

• Units transferred out = Opening WIP (2,000 kg) + Started (18,000 kg) – Closing WIP (3,000 kg) = 17,000 kg

• Closing WIP (3,000 kg)

9.5 T‑Accounts (simplified)

Work‑in‑Process Dept A

Finished Goods (after Dept B) – similar T‑account will be shown after Dept B calculations (omitted for brevity).

9.6 Interpretation

• The average cost per kilogram of tea after Withering is NPR 125.82.
• Closing WIP still holds NPR 323,730 worth of partially processed tea, which will be completed in July.

10. Comparison – Process vs Job Costing

flowchart TB
    A["Process Costing"] --> B["Cost per department"]
    A --> C["Equivalent units"]
    D["Job Costing"] --> E["Cost per individual order"]
    D --> F["Direct tracing of material/labour"]
    B --> G["Suitable for continuous flow"]
    C --> G
    E --> H["Suitable for custom orders"]
    F --> H

11. Real‑world Applications

In the real world

• Daraz – The e‑commerce platform uses a process‑costing approach for its order‑fulfilment centre: items move through receiving, sorting, packaging, and dispatch departments. Costs (labour, handling, packaging material) are accumulated per department and averaged over the number of orders processed each day.

• Ncell – The prepaid recharge system treats each recharge transaction as a unit flowing through validation, billing, and delivery processes. Overhead (server time, network usage) is allocated using equivalent‑unit concepts to determine the cost of each successful recharge.

• NEPSE (stock exchange) – The settlement cycle (trade capture → clearing → settlement) is a continuous process. The exchange allocates operational costs (software licences, staff) to each stage using a process‑costing framework, enabling it to price membership fees based on transaction volume.

These examples illustrate that process costing is not limited to manufacturing; any operation with a repeatable, staged workflow can benefit from the same principles.

12. Common Exam Questions & How to Tackle Them

1. Define equivalent units and compute them for a given department.

   • Write the formula, list physical units, apply % completion for materials and conversion separately.

2. Prepare a production report using weighted‑average method.

   • Start with a table of physical flow, calculate EU, compute cost per EU, allocate to transferred out and closing WIP.

3. Show journal entries for the transfer of costs from one department to the next.

   • Debit the receiving department, credit the sending department with the total cost transferred.

4. Compare FIFO and weighted‑average methods with a short numerical illustration.

   • Highlight that FIFO isolates opening WIP cost, while weighted‑average blends it.

Exam tip:

• Mark the “% complete” column clearly; many marks are lost when students forget to treat materials and conversion separately.
• Always reconcile: opening WIP + costs added = cost of units transferred out + closing WIP. Write a one‑line reconciliation statement at the bottom of the production report – examiners love to see it.
• Use the same unit (kg, litres, pieces) throughout; inconsistent units cause calculation errors.
• For FIFO, first compute the cost of completing opening WIP, then add cost of units started and completed, and finally cost of closing WIP. Present the three parts in separate rows of the allocation table – it makes the answer easy to read and award full marks.

End of Unit 7 – Process Costing