Stock Variance: What Is Causing the Difference Between Your Records and Physical Stock?
You believe your warehouse has 10,000 units in stock. The system says 10,000. The stock ledger says 10,000. But when the physical count is completed, only 9,650 units are found.
Where did the other 350 units go?
This is known as stock variance: the difference between recorded inventory and the quantity physically available. It can result from transaction errors, theft, damaged goods, incorrect product identification, receiving errors, poor documentation, misplaced stock and system synchronization problems.
What Causes Stock Variance?
- Receiving and Recording Errors
A warehouse may receive 500 units but record 550, or receive goods without immediately updating the system.
Case study:
A warehouse receives 200 cartons. The receiving officer records 220 cartons because the supplier’s delivery note was not properly reconciled with the physical count. The system therefore shows 20 cartons that do not actually exist.
- Poor Stock Movement Control
Goods can be moved between locations without the movement being properly recorded.
Case study:
A warehouse transfers 100 units from Warehouse A to Warehouse B. The physical movement takes place, but the system is updated several days later. During an interim stock count, Warehouse A shows a shortage while Warehouse B appears to have excess stock.
- Theft, Loss and Unexplained Shrinkage
Not every variance is caused by an innocent counting error. Theft and unexplained loss can contribute to inventory shrinkage. McKinsey notes that shrinkage can include theft, process errors, waste and discrepancies between book inventory and physical inventory.
- Poor Identification and Labelling
Similar products, incorrect SKU numbers, wrong units of measurement and poor labelling can create significant discrepancies.
For example, a system may record 1 box = 24 units, while an employee counts individual units without correctly converting the quantity.
- Inadequate Counting and Reconciliation
If organizations only conduct a major stock count once a year, discrepancies may remain hidden for months.
Regular cycle counting allows organizations to check selected inventory more frequently and investigate variances closer to when they occur.
Data Analysis: How Serious Can Stock Variance Become?
Consider a hypothetical warehouse with the following results:
| Inventory Indicator | Result |
| System-recorded stock | 10,000 units |
| Physical stock | 9,650 units |
| Stock variance | 350 units |
| Variance rate | 3.5% |
| Average unit value | ₦15,000 |
| Estimated stock value affected | ₦5.25 million |
A 3.5% variance may appear small when expressed as a percentage. However, at an average unit value of ₦15,000, the discrepancy represents ₦5.25 million of inventory value.
The actual financial impact would depend on the organization’s products, accounting treatment and whether the variance represents theft, damage, recording errors, timing differences or other causes.
The wider operational problem is that inaccurate inventory records can lead to poor replenishment decisions, stockouts, excess inventory and unreliable customer commitments. Research from IBM and McKinsey highlights the relationship between inventory accuracy, stock availability and supply-chain performance. (IBM)
What Should Organisations Do?
Businesses should establish a structured inventory-control process covering:
- Accurate receiving and inspection
- Proper SKU identification and labelling
- Authorized stock movements
- Barcode or scanning controls where appropriate
- Regular cycle counts
- Independent reconciliation of physical and system records
- Investigation of significant variances
- Clear accountability for warehouse transactions
- Vendor and delivery-note reconciliation
- Proper documentation of damaged, obsolete and returned stock
Most importantly, organisations should not simply adjust the system to match the physical count. The variance should first be investigated to establish why the difference occurred.
Conclusion
Stock variance is not simply a warehouse problem. It can become a financial, operational, procurement and management problem.
When management cannot confidently answer “What stock do we actually have?”, decisions about purchasing, production, sales and customer fulfilment are being made on uncertain information.
Is Your Organisation Experiencing Inventory Variance?
Rado Professionals provides professional training in Inventory Accuracy, Warehouse Operations, Stock Control, Vendor Management and Supply Chain Operations, helping organisations strengthen processes, improve accountability and reduce preventable inventory losses.
Reach out to us at info@radoprofessionals.com
Call 09168900783 to book for your trainings.
Train your team. Improve inventory accuracy. Strengthen operational control.
