Normal Spoilage
The expected, unavoidable waste or defective units that arise from a production process under efficient operating conditions.
What is Normal Spoilage?
Normal spoilage is the amount of waste, defective units, or lost materials that is considered unavoidable and inherent in an efficient production process. Because normal spoilage is anticipated and controllable only within limits, its cost is included as part of the cost of good units produced — it is treated as a product cost. In contrast, abnormal spoilage exceeds what is expected under normal operating conditions and is expensed immediately as a period cost, signaling a production problem that requires investigation. Setting a normal spoilage threshold requires analysis of historical data and engineering standards. Industries with significant normal spoilage include food processing, textiles, casting, and semiconductor fabrication.
Example
A candy manufacturer expects 2% of production to be lost due to sticking, breakage, and temperature variations — the normal spoilage rate. In a batch of 100,000 units, 2,000 units of normal spoilage are expected. Their cost is spread across the remaining 98,000 good units, raising the per-unit cost slightly. A batch with 8% spoilage would trigger an abnormal spoilage investigation.