Blow Molding & Hollow Plastic Products calculator
Defect Cost Calculator
Defect cost is the full dollar burden of bad containers on a blow molding line — both the variable cost tied up in each rejected bottle and the fixed cost of finding, containing and sorting them. Quality engineers and operations managers use it to turn a reject count into a number finance understands, because a scrap percentage alone never funds a corrective action. It matters because blow molding defects are expensive twice over: you lose the resin, energy and labor already in the part, then you pay people and equipment to catch and segregate it before it reaches a customer. Separating variable from fixed cost shows whether the bigger lever is reducing defects or streamlining containment.
What this calculator does
- Estimate cost of blow molded defects from rejected bottles or containers, average defect cost, allocation share, and fixed containment or sorting costs.
- a blow molding plant needs to quantify the cost impact of rejected containers, sorting, rework, or customer containment
- It computes total defect cost by allocating a per-unit cost across defective containers and adding fixed containment and sorting cost.
Formula used
- Allocated variable defect cost = defective bottles or containers × average cost per defective container × defect cost allocation share
- Total blow molding defect cost = allocated variable defect cost + fixed containment and sorting cost
Inputs explained
- Defective bottles or containers:
- Average cost per defective container:
- Defect cost allocation share:
- Fixed containment and sorting cost:
How to use the result
- Use it when costing a defect event, building a quality cost-of-poor-quality report, or justifying a corrective-action spend.
- The cost per defective container is only as good as your loaded cost data; using bare resin cost instead of fully loaded cost understates the real loss.
Current U.S. benchmarks
- The producer price index for plastic resins and materials stands at 319.371 (BLS, May 2026), up 19.5% from a year earlier. Quotes priced off last quarter's material cost miss this move.
- The U.S. has 9,635 plastics product manufacturing establishments employing about 677,302 workers (Census County Business Patterns, 2023).
Common questions
- How do you calculate blow molding defect cost? Multiply defective containers by the average cost per defective unit and by your allocation share, then add fixed containment cost. With 850 defects at $2.287 each, full allocation and $1,400 fixed, the total is $1,944.
- What does the allocation share mean? It is the percentage of each defective unit's cost you charge to this event — useful when scrap is partly regrind-recovered or shared across departments. At 100% you load the full per-unit cost, as in the $1,944 example.
- Why include a fixed containment cost? Catching defects is not free. Sort labor, extra inspection, quarantine handling and rework setup are fixed per event regardless of unit count. The example's $1,400 is most of the total, which tells you containment effort dominates here.
- What is a good defect cost per container? There is no universal figure — it scales with part size and value. What matters is the trend and the split. In the example the implied $2.287 per defective container is high relative to a sub-cent energy cost, signaling each reject carries real loaded value.
- How is cost per defective container derived? In this example it works back to $2.287 per defect — the loaded value tied up in each bad container including resin, energy, labor and overhead consumed before the part was rejected, not just material.
Last reviewed 2026-05-12.