How to calculate inventory carrying cost
Who it is forGrocery chain finance, buying, supply chain, business owners
"Excess stock is expensive" is a sentence everyone knows and nobody puts a number on. Without a number, buying too much appears to cost nothing: the goods will sell eventually. In reality every unit of currency on the shelf pays a price through the year, and in Türkiye that price exceeds a third of the value of the goods. This guide covers how the rate is calculated, its four components and which decisions depend on it.
What inventory carrying cost is
Inventory carrying cost — also called holding cost — is not what you paid for the goods. It is what you pay after buying them, for as long as they remain unsold.
It is expressed as a percentage because decisions need a rate, not an amount: the answer to "what does holding this for three extra months cost me" comes out of the rate.
Most of the components are already recorded separately in the accounts, but they are never totalled on a single line anywhere. That is why most businesses do not know their own carrying cost — and a number you do not know cannot be used as a decision input.
- Carrying cost rate
(Capital + Storage + Risk + Service) ÷ Average inventory value × 100- Annual cost per unit
Unit cost × Carrying cost rate- Cost of holding a batch
Batch value × Rate × (Days held ÷ 365)
The four components and how each is calculated
The items fall under four headings. The largest is the cost of capital, which in Türkiye makes up more than half the total; the other three together fill the rest.
Cost of capital is the alternative return on the money tied up in stock. If you borrow, it is the interest rate; if you do not, it is what that money would earn on deposit or in the business itself. Not borrowing does not eliminate this cost — that is the mistake made most often.
Risk is the most frequently omitted heading: obsolescence, expiry losses, shrinkage, damage and theft. It is high in fresh departments because of short shelf life and low in ambient grocery. Derive your own risk rate from past years' write-off and markdown data rather than estimating it.
| Component | What it covers | Typical in Türkiye | Typical internationally |
|---|---|---|---|
| Cost of capital | Borrowing rate or alternative return on the money | 25% - 40% | 6% - 12% |
| Storage | Rent, racking, energy, handling, warehouse labour | 3% - 8% | 3% - 8% |
| Risk | Obsolescence, expiry losses, shrinkage, damage, theft | 3% - 15% | 4% - 10% |
| Service | Insurance, counting, inventory administration, tax | 1% - 3% | 1% - 3% |
| TOTAL | 35% - 55% | 18% - 25% |
The rates quoted in international sources are too low for Türkiye and, applied directly, encourage holding excess stock. Take the cost of capital from your own financing rate.
Worked example: one store's annual carrying cost
The calculation runs on average inventory value, not closing stock. In a chain whose stock swings around holidays and promotions, closing stock does not represent the load carried through the year.
Which decisions this rate changes
Carrying cost is not a reporting line but a decision input. When it is unwritten, four decisions drift systematically in the wrong direction.
The first is volume discounts. When a supplier says "6 per cent off if you take double", the answer depends on how long the excess will sit and what that costs. At a 45 per cent rate, goods carried six months longer generate 22.5 per cent of cost; a 6 per cent discount looks small beside it.
The second is economic order quantity: this rate is the formula's denominator. The third is markdown timing — the cost of waiting for a better price comes from here. The fourth is supplier selection: an expensive supplier with a short lead time can beat a cheap one with a long lead time on total cost.
- Volume discounts — does the carrying cost of the excess exceed the discount
- Economic order quantity — this rate is the denominator of the formula
- Markdown timing — the monthly cost of waiting is calculated from here
- Supplier selection — a shorter lead time means less safety stock and less carrying cost
Setting the rate up
The calculation is built once and reviewed annually. When interest rates move quickly, the cost of capital needs an interim update.
- Establish the cost of capitalIf you borrow, the weighted average borrowing rate. If not, the alternative return on the money — the business's own return on capital, not a deposit rate.
- Allocate warehouse costs to stockRent, energy, warehouse labour and handling equipment are totalled and divided by average inventory value. If the warehouse is owned, use a market rent equivalent.
- Derive the risk rate from historySum the last three years' write-offs, shrinkage and markdown losses and divide by average inventory value. Calculate it per category; fresh and ambient grocery differ many times over.
- Add the service itemsInsurance premium, cost of counting, inventory software and the share of staff time.
- Bring it down to category levelA single company-wide rate is enough for rough decisions; ordering and markdown decisions use the category rate.
- Wire it into the buying processVolume discount and bulk purchase offers should automatically show the carrying cost calculated at this rate alongside them. A rate calculated by hand is never used at the moment of decision.
Frequently asked questions
- How is inventory carrying cost calculated?
- Capital, storage, risk and service items are totalled and divided by average inventory value. In a store with average inventory of ₺155,000 where those items come to ₺69,750, the carrying cost rate is 45 per cent.
- What is included in inventory carrying cost?
- Four headings: cost of capital (the alternative return on the money tied up in stock), storage (rent, energy, handling, warehouse labour), risk (obsolescence, shrinkage, damage, theft) and service (insurance, counting, inventory administration). The purchase price of the goods is not included; that is cost of goods sold.
- What should the inventory carrying cost rate be?
- There is no single rate; it is calculated from the business's own financing cost, storage, risk and service. International figures were calculated in low-interest environments; in Türkiye, where the cost of capital is high, the rate runs well above them. Using a foreign benchmark directly encourages holding excess stock.
- If I do not borrow, is my cost of capital zero?
- No. Even without borrowing, the money tied up in stock was placed there by giving up an alternative return. The correct measure is the business's own return on capital; not borrowing does not remove this cost, it only makes it invisible.
- When should a volume discount be accepted?
- When the discount gain exceeds the additional carrying cost of the excess goods. An average of ₺116,600 of extra goods carried for six months at a 45 per cent rate costs ₺26,235; with a discount gain of ₺22,200 the discount loses ₺4,035. The break-even is a carrying rate of about 38 per cent.
- What is the difference between carrying cost and cost of goods sold?
- Cost of goods sold is what you paid for the goods and is expensed when they sell. Carrying cost is what it costs to hold them until they sell, and it accrues every day whether they sell or not. The second never appears on a single line in any ledger account.