When a lower packaging unit price increases total cost

Define the purchasing question

A supplier price break can reduce price per piece while increasing cash committed, storage and obsolete-stock exposure.

Compare initial purchase cash separately from holding and inventory exposure. Requote freight and quantity tiers for each purchase option; do not reuse a price valid only at a different tier.

Collect measurements that match the calculation

Record demand needed now, the rounded purchased quantity, usable surplus, expected retention period and actual storage charges. Use a capital-cost assumption only when its scope is understood.

This snapshot holds surplus constant during the entered interval. It is for stock not consumed during that time, not a continuous drawdown model. Keep initial material cash separate from holding expense.

• Units needed now (units)
• Purchased quantity after MOQ rounding (units)
• Purchase price per unit (currency)
• Months surplus held unchanged (months)
• Storage per surplus unit per month (currency)
• Annual simple capital rate (%)

Work through an illustrative case

Holding = (Purchased − Required) × Months × (Storage/month + Price × Annual capital rate/1,200)

5,000 surplus units × 3 months × EUR 0.003/unit-month gives EUR 45 holding expense.

Replace these illustrative inputs with measured data or a quotation for the same scope. Change one assumption at a time so that a difference can be traced to a dimension, quantity, charge or process change.

Avoid the expensive comparison error

Treating all bought stock as consumed demand hides surplus. Conversely, charging constant surplus holding when stock is steadily consumed overstates that specific holding scenario.

• Use measured quantities and charges valid for this exact specification and period.
• Cost calculations do not qualify performance, protection or a supplier.

Case: a discount creates extra cash commitment

Demand is 10,000 usable packs. Buying exactly that quantity at EUR 0.20 costs EUR 2,000 before other charges. A EUR 0.18 price available only at 15,000 packs requires EUR 2,700 and leaves 5,000 packs of nominal surplus.

The discount lowers purchased-unit price but increases the current material payment by EUR 700. Whether retained surplus is useful depends on future demand, artwork validity and storage; do not count it automatically as waste or a saving.

Common questions