Ask most founders what it costs to hold stock and the answer is the warehouse bill. That is one of four components. It is usually not the biggest. The largest never arrives as an invoice at all. It is the money sitting in the rack, and it cannot be doing anything else while it is there.
The four components are easy to name and awkward to size. This page sizes each one from numbers you already have, then works a single product end to end.
What are the four components?
Capital, storage, service, and risk. The meaning of each is worth pinning down before you size it. Capital is the return the money could earn elsewhere. Storage is space and its utilities. Service is handling, counting, insurance and administration. Risk is the value the stock loses while it waits — which for dated goods is the whole ballgame.
| Component | What it covers | How to size it |
|---|---|---|
| Capital | Money tied up in stock | Your real cost of funds, or the return on the next thing you would fund |
| Storage | Space, racking, utilities, third-party fees | Rent or 3PL bill, divided by average stock value |
| Service | Handling, counting, insurance, admin | Hours plus premiums, annualised |
| Risk | Damage, obsolescence, expiry | Last year's write-offs over average stock value |
The sizing method that matters is the last one: use your own write-offs from last year rather than an industry percentage. It is the component that varies most between operations and the one a borrowed figure gets most wrong, because it depends entirely on your shelf lives and your buying discipline.
How do you calculate carrying cost?
The inventory holding cost formula is an addition rather than an equation. Add the four components as percentages of average stock value and the total is your carrying rate. Multiply that rate by the stock value you hold, then divide by twelve for a monthly figure. Calculate the rate once and it applies to every buying decision after it.
| Line | Value | How it was sized |
|---|---|---|
| Average stock value held | 40,000 | Twelve-month average, at cost |
| Capital | 12% | Return on the production run it did not fund |
| Storage | 4% | 3PL bill over average stock value |
| Service | 3% | Handling, counting, insurance, admin |
| Risk | 9% | Last year’s write-offs over average stock value |
| Carrying rate | 28% | The four added together |
| Cost per month | 933 | 40,000 at 28%, divided by twelve |
Size it once across the whole operation, then vary one line per product. Capital, storage and service barely differ between your products, so a single company-wide figure is honest enough for all three. Risk does not behave that way. A product with ninety days of shelf life and one with two years cannot share a risk percentage. So set the company rate once, then adjust only the risk line product by product, and leave the other three alone.
Why is capital the line founders forget?
Because it never arrives as a bill. Rent invoices, insurance renews, staff get paid — each one announces itself. The cost of money sitting in stock announces nothing at all, and a brand that paid cash for its inventory often concludes that the capital component is therefore zero.
It is not zero; it is the return on whatever that money would otherwise have funded. For an early brand that alternative is rarely a savings rate. It is a production run that would have earned a margin, a retail listing that needed a fee, or the hire that got deferred. Priced against those, capital is frequently the largest of the four components and the one that most changes a buying decision.
Getting this right matters because it is the term that makes over-buying visibly expensive. Without it, holding an extra three months of a slow SKU looks close to free — some racking, a bit of admin. With it, the same decision is obviously the most expensive thing on the shelf, which is what the markdown ladder ends up cleaning up months later.
What changes for dated goods?
Risk stops being a small allowance and becomes the dominant term. In most industries obsolescence is a modest percentage covering damage and slow decline. With a date on the pack it is a near-certainty on any stock held past its selling window, which makes carrying cost rise sharply with time rather than gently.
That is the practical consequence: the cost does not rise in a straight line. Elsewhere, holding stock twice as long costs roughly twice as much. Here, holding it twice as long can cost far more than twice as much, because part of the second period carries a real probability of the stock being worth nothing at all. Averaging that into a flat annual percentage hides exactly the effect you needed the number for.
The useful form is therefore per-SKU and time-shaped rather than a single company-wide rate: what does holding this item cost per month, and how does that change as the date approaches? That framing feeds the buying decision directly, and it is the same ceiling that governs how much buffer the selling window absorbs.
What should you do next?
One afternoon to size it, then use it when buying.
Size the four
- Set capital at the return on the next thing you would fund.
- Divide rent or 3PL fees by average stock value.
- Take risk from last year’s actual write-offs.
Make it per-SKU
- Express the result as a cost per month, not an annual percentage.
- Show how it changes as the date approaches.
Use it
- Price the carrying cost into every buying decision above a threshold.
- Compare it against what a stockout would have cost.
Frequently asked questions
What is included in inventory carrying cost?
Four components: the capital tied up in the stock, storage, handling and insurance, and the risk of the stock losing value. For food and drink the risk component is dominated by dating, which makes it larger and far more predictable than in most industries.
What percentage is typical for carrying cost?
Rules of thumb put it around a fifth to a third of inventory value a year, but the range is wide enough that a borrowed figure is close to useless. Work out your own four components once; the exercise takes an afternoon and the answer stays roughly true.
Why does capital cost count if I paid cash?
Because the money still has an alternative use. Cash sitting in stock is cash not funding a production run, a listing fee or a hire. Paying cash removes the interest line, not the cost.