Inventory carrying cost for sourced packaging is the cost of holding packaging stock until it is used. The basic calculation is average inventory value × annual carrying rate × holding period in years. Average inventory value should be based on landed unit cost—factory cost plus tooling amortization, freight at the real mode, duties, inserts or assembly, defect allowance, and warehousing—not on the ex-works factory quote alone [1].
What the calculation includes
Carrying cost is broader than warehouse rent. It normally includes capital tied up in stock, storage and handling, insurance, taxes where applicable, obsolescence, damage, shrinkage, and inventory administration. The packaging landed-cost guide treats carrying cost as a real profit-and-loss line and gives an annualized planning range of 18–25% [1]. The exact rate should be set with finance because it depends on the cost of capital and the risk profile of the packaging.
Define the boundary between landed cost and carrying cost before calculating. If warehousing is already included in the landed unit cost [1], do not add the same storage charge again in the carrying rate. Either use a landed cost that excludes warehousing and put storage in the carrying rate, or use fully landed cost and remove storage from the rate. The important point is consistent treatment, not a particular accounting convention.
Inputs and formulas
Four inputs drive the result:
- Landed unit cost. Use the planned landed cost for the packaging SKU. The factory unit cost is often 60–85% of landed cost, so the remaining components can materially change the inventory value being carried [1].
- Average inventory quantity. For steady demand and no safety stock, cycle stock averages about half the order quantity. Add safety stock and any in-transit inventory the business owns. For multiple SKUs, calculate the value for each SKU and sum.
- Annual carrying rate. Express the rate as a decimal. An 18–25% annualized planning range is a useful reference [1], but the rate should reflect the organization’s capital, storage, insurance, obsolescence, and handling costs.
- Holding period. Use years for an annual rate. For months, divide the number of months by 12. For a monthly rate, divide the annual rate by 12.
Core formulas:
- Average inventory value = average units on hand × landed unit cost.
- Carrying cost for a period = average inventory value × annual carrying rate × holding period in years.
- Carrying cost per unit consumed = carrying cost for the period ÷ units consumed in that period.
The last formula is useful for quoting and margin models because it converts a holding cost into a per-unit add-on. It should not be confused with the carrying cost per average unit in stock.
Worked example with illustrative figures
Assume a buyer sources 100,000 printed cartons for a 12-month launch. The landed unit cost is $1.20, and demand is steady at about 8,333 units per month. There is no safety stock. Average inventory is therefore 100,000 ÷ 2 = 50,000 units, and average inventory value is 50,000 × $1.20 = $60,000. At a 22% annual carrying rate, the annual carrying cost is $60,000 × 0.22 × 1 = $13,200. Divided by 100,000 units consumed, the carrying cost is $0.132 per unit, or 11% of the landed unit cost.
If the buyer orders a six-month supply of 50,000 units instead, average inventory is 25,000 units and average inventory value is $30,000. For a six-month holding period, carrying cost is $30,000 × 0.22 × 0.5 = $3,300. Per unit consumed over the period, that is $3,300 ÷ 50,000 = $0.066. These numbers are illustrative and are not supplier quotes; changing the rate, safety stock, demand pattern, or landed cost changes the result.
How sourcing choices change carrying cost
MOQ and order quantity. A larger order lowers the average unit price in some negotiations, but it also raises average inventory and the time stock sits on the balance sheet. The packaging guide describes MOQ above launch volume as inventory sitting on the balance sheet, not free upside [1]. A price-break analysis should compare the saving on the order with the carrying cost of the extra units, plus obsolescence risk for printed or customized packaging.
Freight mode and lead time. Freight mode changes the landed number by 2–4x, according to the guide, so it should be planned rather than handled as an emergency [1]. Freight affects carrying cost in two ways: it changes landed unit cost, and slower transport can increase pipeline inventory. If the business owns goods in transit, include that inventory in the average; if it does not, remove it.
Safety stock and reorder policy. Long supplier lead times, uncertain demand, and quality checks usually require safety stock. Safety stock raises average inventory and therefore carrying cost even when the cycle stock is unchanged. A reorder point that ignores carrying cost can make a cheap packaging quote look better than it is.
Defects and customization. Defect allowance, assembly, and inserts are part of landed cost planning [1]. Custom-printed or season-specific packaging may also carry higher obsolescence risk. If that risk is not in the annual carrying rate, add it explicitly rather than assuming a generic rate captures it.
Common mistakes and checks
- Using the factory quote as inventory value. This understates the capital tied up because freight, duties, tooling amortization, inserts, defect allowance, and warehousing are omitted [1].
- Mixing time periods. An annual rate applied to a six-month holding period without a 0.5 factor overstates cost; a monthly rate applied to a year understates it.
- Counting only rent. A rent-only rate misses capital, insurance, obsolescence, damage, and administration. The 18–25% annualized reference is a reminder that carrying cost is more than storage [1].
- Double-counting warehousing. If warehousing is in landed cost, remove it from the carrying rate or use a landed cost excluding warehousing.
- Ignoring safety stock or owned pipeline inventory. Both increase average inventory value and should be included when they exist.
- Treating a price break as a net saving. Compare the unit-price saving with the carrying cost and risk of the additional inventory, especially when MOQ exceeds launch demand [1].
Decision summary
To calculate carrying cost for sourced packaging, first establish a landed unit cost for each packaging SKU and document which cost components are included. Then forecast demand and calculate average cycle stock, safety stock, and any owned in-transit stock. Agree an annual carrying rate with finance, convert the holding period to years, and apply the formula. Finally, divide the result by units consumed to get a per-unit carrying charge and compare it with MOQ price-break savings, freight choices, and lead-time decisions. Recalculate when the supplier, freight mode, order quantity, or launch forecast changes.
FAQ
What annual carrying rate should I use for sourced packaging?
Use a finance-approved rate. The packaging landed-cost guide cites 18–25% annualized as a planning range and notes that carrying cost is a real profit-and-loss line [1]. The rate should reflect capital, storage, handling, insurance, obsolescence, and administration, with warehousing treated consistently to avoid double counting.
Should freight be included in the inventory value used for carrying cost?
Yes, if freight is part of landed unit cost. The guide includes freight at the real mode in the landed-cost stack [1]. Freight also matters for pipeline inventory: include in-transit stock only when the business owns it.
How does MOQ affect inventory carrying cost?
A larger MOQ raises average inventory and holding time. MOQ above launch volume is inventory on the balance sheet, not free upside [1]. Compare the price-break saving with the extra carrying cost and obsolescence risk before accepting the larger order.