Inventory Carrying Cost

Only the storage part of carrying cost arrives as an invoice. Capital cost is the return the company gives up by keeping money in inventory rather than elsewhere; service cost covers insurance, taxes, handling and counting; risk cost covers obsolescence, shrinkage, damage and the markdowns taken to clear stock that has aged. None of those three land in a cost centre labelled “inventory”, so the rate has to be constructed rather than read off the ledger.

• Carrying cost rate = (capital + storage + service + risk cost) ÷ average inventory value, measured over the same period, normally a year.
• Carrying cost of an item = unit cost × average units held × rate – the form that goes into EOQ, safety stock sizing and forward buying decisions.

Inventory carrying cost in practice

The 20 to 25% a year quoted in textbooks is a starting point, not a number to adopt. Its largest component is the cost of capital, and that is the company’s own WACC rather than an industry constant: when financing costs move, the same physical stock becomes a different expense, and a rate set years ago and never revisited pushes every order quantity and every forward buy in the same direction. The second trap is one company‑wide rate spread over a mixed assortment. Risk cost varies between categories far more than capital does – in fresh food, cosmetics or fashion, write‑offs and markdowns can outweigh the capital component, while for slow‑moving spare parts the ratio is reversed.

The rate matters most at the moment of ordering, where a 5% quantity discount shows up on the invoice and the cost of the extra months of cover shows up on none. Veritico STOCK evaluates buying decisions of that kind – quantity discounts and forward buying ahead of an announced price increase – against the cost of holding the additional stock, calculating with WACC and looking for the break‑even; it also reports overstock in money rather than units. See demand forecasting and inventory optimization and replenishment and allocation management.

Related terms

• Economic Order Quantity (EOQ)
• Inventory Turnover
• Overstock
• Dead Stock
• Forward Buying
• Days of inventory outstanding (DIO)