Inventory shrinkage is the gap between the stock your records say you should have and what a physical count actually finds. It comes from four main causes, theft, damage, administrative error, and expiry, and is measured using a simple formula: recorded stock value minus actual counted stock value, often expressed as a percentage of expected inventory.
What is inventory shrinkage, exactly?
Every business that carries physical stock has a record of what it should have: a running total based on what was bought in and what was sold out. Inventory shrinkage is what's left when that record doesn't match reality: the difference between the stock count your system expects and the stock count you actually find when you physically check the shelves or storeroom. It's called "shrinkage" because from the business's perspective, stock has simply disappeared relative to what the books say.
Common causes of shrinkage
Theft
Both staff theft and customer theft (shoplifting) fall under this cause. Staff theft can range from a cashier pocketing cash and not recording the sale, to stock walking out the back door. Customer theft is more visible but often smaller in total value than internal theft in businesses with weak controls.
Damage and spoilage
Breakages, water damage, and, for perishable goods, spoilage before sale all reduce sellable stock without a corresponding sale being recorded. This is usually the most "innocent" category of shrinkage, but it still needs to be tracked and written off correctly.
Administrative error
Mistakes in recording a sale, miscounting stock received from a supplier, entering the wrong quantity into the system, or pricing errors that cause a mismatch between what was charged and what was recorded: all of these create a gap between records and reality without any theft or damage actually occurring.
Expiry
Stock that passes its expiry or use-by date and has to be written off is a distinct cause from damage: the product itself may be undamaged, but it's no longer sellable. Businesses with perishable stock (supermarkets, bakeries, pharmacies, agrovets) tend to see a meaningfully higher expiry-driven shrinkage rate than those selling durable goods.
The stock-variance formula
| Term | What it means |
|---|---|
| Recorded stock value | What your system says you should have, based on purchases minus recorded sales |
| Actual counted stock value | What a physical stock take actually finds on the shelf or in storage |
| Shrinkage (value) | Recorded stock value minus actual counted stock value |
| Shrinkage (%) | (Shrinkage value ÷ recorded stock value) × 100 |
Expressing shrinkage as a percentage rather than a raw value makes it possible to compare shrinkage across different time periods, product categories, or even between branches of a multi-location business: a raw value alone doesn't tell you whether shrinkage is getting better or worse relative to how much stock you're actually carrying.
Why measuring shrinkage matters more than reacting to it
A shrinkage figure on its own is just a number. Its real value comes from tracking it consistently over time and by category, so you can spot patterns: a specific product category with unusually high shrinkage, a particular shift or branch with a persistent gap, or a rising trend that wasn't there a few months ago. That pattern is what tells you whether you're looking at routine damage and admin error, or something that needs closer attention.
Regular stock counts, matched against your POS's recorded stock levels, are the foundation of measuring shrinkage accurately. For a step-by-step process, see Stock Management for Kenyan Businesses, and for what to do once a pattern points toward theft specifically, see Preventing Staff Theft in Kenyan Retail Shops.
Frequently asked questions
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