Your inventory system says you have 120 units of a product. But when your warehouse team checks the shelf, only 113 units are available.
Seven units are missing.
Was there an unrecorded sale? Did someone enter the wrong quantity? Or were some products damaged and removed without updating the system?
This situation is known as an inventory discrepancy, and it’s a common challenge for businesses managing physical products.
Even small stock differences can create problems. Customers may purchase unavailable products, warehouse employees may waste time searching for missing items, and purchasing decisions may rely on inaccurate information.
Understanding why discrepancies happen is the first step toward maintaining reliable inventory records.
What Is an Inventory Discrepancy?
An inventory discrepancy occurs when the quantity recorded in an inventory system doesn’t match the actual physical stock.
For example, your inventory software shows 80 units of a product, but a physical count reveals only 75.
The difference of five units represents an inventory discrepancy.
Discrepancies can be positive or negative.
A negative discrepancy occurs when physical inventory is lower than the recorded quantity.
A positive discrepancy occurs when physical inventory exceeds the system quantity.
Both situations indicate that inventory records need investigation.
Inventory Discrepancy Examples
Consider a small ecommerce business selling packaging supplies.
The company maintains inventory records for several products.
| Product | System Stock | Physical Stock | Difference |
|---|---|---|---|
| Glass Bottle 250 ml | 150 | 143 | -7 |
| Cream Jar 100 ml | 200 | 205 | +5 |
| Plastic Pump Bottle | 80 | 80 | 0 |
| Amber Glass Bottle | 120 | 116 | -4 |
The glass bottle has seven fewer units than expected, while the cream jar has five additional units.
These differences require investigation before adjustments are made.
Simply changing the recorded quantity without identifying the cause may hide an ongoing operational problem.
7 Common Causes of Inventory Discrepancies
1. Human Data Entry Errors
Manual inventory updates are vulnerable to mistakes.
An employee might record 50 units instead of 15 or forget to enter a stock adjustment.
These errors can accumulate over time, especially when several employees manage inventory records.
2. Unrecorded Stock Movements
Products sometimes move between storage locations without proper documentation.
For example, warehouse employees may transfer 20 units from the main storage area to a packing station.
If the movement isn’t recorded, the system may show incorrect quantities at each location.
3. Incorrect Order Fulfillment
Picking errors can create inventory discrepancies.
Imagine a customer orders five units, but the warehouse accidentally ships six.
The system deducts five units while six physically leave the warehouse.
The resulting difference may remain unnoticed until the next stock count.
4. Damaged or Lost Products
Products can break, leak, expire, or become unsuitable for sale.
If damaged items are discarded without an inventory adjustment, the recorded stock becomes inaccurate.
This is particularly relevant for fragile products such as glass bottles and cosmetic containers.
5. Supplier Delivery Differences
Purchase orders don’t always match received quantities.
A supplier may invoice 500 units while the warehouse physically receives 495.
If employees record the invoiced quantity without checking the shipment, inventory records become incorrect immediately.
6. SKU and Product Variation Errors
Products with similar appearances can be confused during receiving or fulfillment.
For example, two bottles may share the same design but have different capacities.
If employees record the wrong SKU, one product may show excess inventory while another shows a shortage.
7. Multichannel Inventory Synchronization Problems
Businesses selling through multiple marketplaces may experience stock differences when inventory updates are delayed or fail.
For example, a product sells through one marketplace, but the updated quantity doesn’t reach another connected platform.
This can result in overselling or inconsistent inventory records.
How to Calculate Inventory Discrepancy
The basic calculation is straightforward.
Inventory Discrepancy = Physical Stock − Recorded Stock
Suppose your system records 250 units, but your physical count identifies 238 units.
Inventory Discrepancy = 238 − 250
Result: -12 units
This indicates a shortage of 12 units.
You can also calculate the discrepancy percentage:
Discrepancy Rate = (Absolute Difference ÷ Recorded Stock) × 100
Using the same example:
(12 ÷ 250) × 100 = 4.8%
This means the difference represents 4.8% of the recorded quantity.
For meaningful comparisons, use a consistent calculation method across reporting periods.
How to Fix Inventory Discrepancies
Resolving stock differences requires a systematic approach.
Step 1: Recount the Physical Inventory
Before changing inventory records, verify the actual quantity.
Count the affected products again and check nearby storage locations.
Make sure the count includes the correct SKU and product variation.
Step 2: Review Recent Transactions
Examine recent sales, purchase receipts, returns, transfers, and stock adjustments.
Look for transactions that were missed, duplicated, or recorded incorrectly.
For example, an unrecorded return may explain why physical stock exceeds the system quantity.
Step 3: Check Receiving and Shipping Records
Compare purchase orders against receiving documents.
Review fulfillment records to identify potential picking or packing errors.
If discrepancies involve several related SKUs, investigate whether products were mixed during warehouse handling.
Step 4: Identify the Root Cause
Determine why the discrepancy occurred.
Possible explanations include incorrect data entry, damaged inventory, supplier shortages, or synchronization failures.
Document the findings rather than relying on assumptions.
Step 5: Adjust Inventory Records
Once the physical quantity and cause have been verified, update the inventory system according to your company’s procedures.
Record the adjustment reason, date, quantity, and responsible employee.
This creates an audit trail for future reviews.
Step 6: Prevent the Problem From Recurring
Use the investigation results to improve the workflow.
If receiving errors are common, introduce quantity verification.
If employees frequently confuse variations, improve SKU labels and storage organization.
The goal is to correct both the inventory record and the process that caused the difference.
How to Prevent Inventory Discrepancies
Preventing discrepancies is usually more efficient than repeatedly correcting them.
Start with consistent SKU identification.
Every product and variation should have a clear identifier that employees can recognize.
Next, establish standardized procedures for receiving, picking, packing, returns, and stock adjustments.
Regular cycle counting can also help.
Instead of counting the entire warehouse at once, cycle counting involves checking selected inventory items on a recurring schedule.
High-value or fast-moving products may require more frequent checks.
Businesses should also review inventory synchronization across connected sales channels.
Automation can reduce repetitive manual work, but it still requires accurate source data and reliable integrations.
Inventory Discrepancy vs. Inventory Shrinkage
These terms are related but not identical.
Inventory discrepancy describes a difference between recorded and physical inventory.
Inventory shrinkage generally refers to inventory losses caused by factors such as theft, damage, administrative errors, or other unexplained losses.
Not every discrepancy represents actual inventory loss.
For example, a misplaced product may eventually be found in another storage location.
Investigating the difference helps determine whether the issue involves recordkeeping, physical loss, or another operational problem.
When Should You Investigate Inventory Differences?
Ideally, businesses should investigate discrepancies as soon as they are discovered.
However, investigation priorities may depend on product value, quantity, frequency, and operational impact.
A shortage of two inexpensive items may be less urgent than a recurring discrepancy involving high-value inventory.
Repeated differences involving the same SKU deserve particular attention.
They may indicate a weakness in receiving, fulfillment, or inventory recording procedures.
Final Thoughts
Inventory discrepancies are more than simple counting mistakes.
They can affect order fulfillment, purchasing decisions, customer satisfaction, and operational efficiency.
The most effective approach combines accurate physical counts, transaction reviews, documented adjustments, and preventive controls.
For ecommerce businesses, consistent SKU management and reliable inventory synchronization are especially important.
Accurate inventory isn’t just about knowing how many products you have. It’s about being able to trust the numbers when making business decisions.