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Microlesson · 5-min read

Job Costing – Concept and Treatment of Spoilage / Defectives

# Job Costing

Job Costing is applied where production is undertaken against specific customer orders with unique requirements. Each job is treated as a separate cost unit; all materials, labour and overheads are accumulated against it so a price can be quoted and profitability measured per job.

It builds on concepts from earlier chapters – Cost Sheet, Material, Labour and Overheads – and applies them to a single, identifiable job.

## Spoilage vs Defectives

TermMeaning
Spoiled productCannot be rectified – totally out of use.
Defective productCan be made good by extra (rectification) work.

## Treatment of Defectives – Three Cases

1. Defects are normal to production

  • Cost of rectification is spread over the entire batch / good output.

2. Defects arise due to abnormal reasons (e.g., bad workmanship, accident)

  • Cost of rectification is transferred to Costing P/L – not loaded on good production.

3. Defects due to negligence of the Material Inspection Department

  • Cost of rectification is charged to the Material Inspection Department (departmental responsibility).

This matches the standard normal/abnormal treatment used throughout cost accounting – normal losses become part of cost, abnormal losses hit P/L, and controllable losses are charged to the responsible department.

Worked example

### Example 1

Example – Defective Units, Normal

A job batch of 1,000 units gives 50 defective units; rectification cost ₹2,000. Normal level of defectives is 5%.

Since 50 units = 5% (normal), the ₹2,000 rectification cost is absorbed by the good output:

Additional cost per good unit = ₹2,000 / 950 ≈ ₹2.11.

### Example 2

Example – Defectives due to Inspector's Negligence

Rectification cost ₹6,000 traced to poor inspection.

```

Material Inspection Dept a/c Dr 6,000

To WIP / Costing P&L a/c 6,000

```

The department's cost is increased; the job itself is not burdened.

⚠️ Common exam mistakes

  • Treating all defective work as abnormal – defects within normal limits must be absorbed by good output, not charged to P/L.
  • Confusing spoiled units (scrapped) with defective units (rectifiable). Spoilage involves disposal/scrap value; defectives involve extra cost.
  • Forgetting to identify the cause of defectives before deciding the accounting treatment – the same rupee cost can be allocated three different ways.
Reference:
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