A client asks you to stop shipping one lot of shampoo after its supplier reports a quality issue. You can see the total stock for that SKU, but the client needs more detail: where is the affected lot, how much remains, and which orders have already received it?
Warehouse lot tracking connects each lot to its receipts, storage locations, movements, and shipments. Those records help your team locate the relevant stock and identify where shipped quantities went.
In a 3PL warehouse, the records must also identify the inventory owner. Different clients may use similar product names or lot codes, so the search needs to stay tied to the right account.
What Is Warehouse Lot Tracking?
Warehouse lot tracking keeps a record of each lot as stock arrives, changes locations, and leaves in customer orders. Staff can follow a specific group of products even when several lots share the same SKU.
A lot number refers to the set of products associated with conditions determined by the manufacturer or supplier. The conditions could be a production run, manufacturing line, or processing time period. The format varies from organization to organization; a warehouse should never assume it understands a code without access to that additional information.
A warehouse can hold several lots of the same product at the same time. Only tracking total quantity conceals those distinctions. Lot tracking keeps track of the location of each lot, how much of it is left, and where the shipped amounts went.
How Lot Numbers Differ From SKUs and Serial Numbers
A SKU is used to identify and track a product in an inventory management system. For example, a brand might have SKU SH250 for a 250ml shampoo.
The lot number differentiates a specific batch of that shampoo. In the warehouse, there could be 120 units of lot L2408 and 80 units of lot L2409 all with the same SKU.
A serial number is unique to a specific unit. Two units from a given lot can have different serial numbers but the same lot number. GS1 distinguishes between identification of products, identification at the lot level, and identification of individual units. www.gs1.org
Expiration dates are separate attributes. Two lots may expire on the same date, and products without expiration dates may still need lot tracking for quality investigations.
The terms “batch” and “lot” are often used interchangeably. If a client distinguishes between them, agree on how each will be recorded before receiving its inventory.
Why Lot Tracking Matters in a Warehouse
When a customer raises an issue, lot records enable the warehouse to focus its search. Staff can locate the affected stock and identify relevant shipments instead of treating every unit of the SKU as potentially involved. That can reduce unnecessary handling and disruption, provided the affected scope has been confirmed.
The records are also useful during everyday operations. When linked to expiration dates, they support stock rotation and customer shelf-life requirements. They help teams investigate repeated returns, explain quantity discrepancies and answer questions about a specific delivery.
For a 3PL, this allows for more specific client reporting. Instead of saying that 50 units remain, the warehouse can explain which lot those units belong to, where they are stored, and whether they are available, allocated, or on hold.
How Lot Tracking Works From Receiving to Shipping
Lot information needs to survive ordinary warehouse work: opening cartons, splitting pallets, replenishing picking bins, and changing an order’s allocation.
Record the Lots That Actually Arrive
During the warehouse receiving process, check the lot information on the physical goods against the supplier’s documents or advance shipping notice.
Check the lot codes before closing the receipt. A delivery can contain more than one lot, and a lot received last week may appear in today’s shipment too.
If 200 units arrive across two lots, enter the quantity for each. The combined total will not tell the picking team how much stock is available from either one.
Copy the supplier’s or manufacturer’s code as shown, including punctuation and leading zeros. If your warehouse adds its own reference, keep it linked to that original code.
Missing or unreadable labels need a clear exception process. Staff should know where to place the stock, who can confirm its lot, and whether picking must wait until the information is resolved.
Preserve Identification When Stock Moves
After receiving, the location records should show which lots occupy each bin, pallet, or other handling unit.
Separate bins can make this easier, although some operations store multiple lots in one location. In either arrangement, staff must be able to identify the stock they are handling.
Problems often begin when an outer carton carries the only lot label. Once the carton is opened and its contents are distributed, the connection can disappear. Before splitting stock during putaway, establish how each portion will remain identified.
Record replenishment and warehouse transfers against the relevant lot. If goods move from reserve storage to a picking bin, both the quantity and location history should reflect that movement.
Confirm the Lot Actually Picked
An allocation records what the system intends to ship. The completed transaction needs to record what staff actually picked.
Suppose an order is allocated to L2408, but the picker takes the same SKU from L2409. The product may be correct, yet the traceability record is wrong unless the substitution is recorded.
Provide a clear process for approved substitutions. Where an order uses multiple lots, retain the quantity picked and shipped from each one.
Barcode scanning can help verify the selection, but a product barcode alone may not identify the lot. Some barcode formats carry product, lot, and date information in separate fields, which compatible scanners and software must interpret correctly. ref.gs1.org
Connect Lots to Shipments and Exceptions
At dispatch, retain the connection between the confirmed lot quantities, order, shipment reference, dispatch date, and recipient.
For a split order, each shipment needs its own record of the lots included. If stock is damaged, adjusted, returned, or disposed of, record the transaction against the affected lot and retain the reason and authorization.
These changes should leave an audit trail. Someone investigating the lot later needs to understand why its balance changed.
What Information Should a Lot Record Include?
A practical record connects inventory identity with its transaction history. The exact fields depend on the operation, but a warehouse should normally be able to retrieve:
- Identity: Client or owner, product or SKU, manufacturer or supplier, and original lot code.
- Dates: Receipt date and any applicable production, best-before, or expiration dates, stored as distinct fields.
- Stock position: Warehouse, location or handling unit, quantity, unit of measure, and stock status.
- History: Receipt references, movements, adjustments, returns, and associated users and timestamps.
- Dispatch details: Order and shipment references, quantities shipped from each lot, dispatch dates, and recipients.
Be careful with units of measure. A receipt recorded as 20 cases cannot be reconciled with shipments recorded as individual units unless the case quantity and conversions are defined.
The information may sit across several WMS screens or reports. What matters is whether the team can retrieve the connections without rebuilding them manually.
Tracing a Lot Backward and Forward
A returned item can start a backward search: which lot does it belong to, which receipt brought it into the warehouse, and which supplier delivered it?
A supplier’s quality notice starts the search in the other direction: where is the affected inventory now, and which shipments contained it?
Warehouse records should support both searches within the operation’s scope. A 3PL may have receipt and shipment records without access to the manufacturer’s production history. Its role is to preserve the information it receives and provide reliable records of its own handling.
A Warehouse Lot-Tracking Example
Consider a hypothetical delivery for Client North. The warehouse receives 120 units of shampoo SKU SH250 from lot L2408 and 80 units from L2409.
After several days of fulfillment, the records show:
| Lot | Received | Shipped | Remaining on Hand | Current Locations |
|---|---|---|---|---|
| L2408 | 120 units | 70 units | 50 units | 30 in A-01; 20 in B-03 |
| L2409 | 80 units | 20 units | 60 units | 60 in C-02 |
The client asks the warehouse to hold L2408 while it investigates a quality concern.
Staff can locate the 50 remaining units across two bins and prevent further allocation under the agreed procedure. Shipment records show that Order N101 received 40 units from L2408 and Order N108 received 30.
The 120 units received reconcile to 70 shipped and 50 still on hand. Placing those 50 units on hold changes their availability, not their physical quantity.
This example assumes no returns, damage, or other adjustments. In a live investigation, check those transactions too. Stock already picked or packed but not dispatched must also be located and included in the hold where applicable.
Common Gaps in Warehouse Lot Tracking
A lot field in the system does not guarantee usable records. The gaps tend to appear when staff encounter something the normal workflow does not handle well.
Returns With Uncertain Lot Identity
Start with the original shipment record, then check the returned goods. The parcel may contain a different item, mixed products, or packaging with an unreadable lot code.
If the lot cannot be confirmed, set the goods aside for review under the client’s procedure. Choosing a lot simply to complete the entry leaves the next person with a record they cannot trust.
Kits That Lose Their Component History
A kit’s component list tells you which products went inside. To trace a problem lot, you also need to know which component lots were used in that assembly.
Where that traceability is required, connect the component lot numbers and quantities to the kit’s assembly record. Keep the same connection when goods are repacked or relabeled.
Adjustments Made Only at SKU Level
A count can match the SKU total while revealing that the lot balances are wrong. The system might show 30 units of L2408 and 20 of L2409, while staff find 25 of each. There are still 50 units, but the split needs correcting.
Counts and corrections need to verify the identity and the quantity.
Client Information Missing From Searches
Two clients may use the same SKU name or lot code. Include the inventory owner in searches and exports so staff can tell whose goods they are handling.
Warehouse staff with the right permissions may need to search across accounts. A client’s portal and reports, however, should show only the information that client is authorized to access.
Lot Tracking, FIFO, and FEFO
Lot records tell you which stock you have and what has happened to it. Rotation rules help decide which eligible stock to pick next.
FIFO, or first in, first out, generally gives priority to earlier receipts. FEFO, or first expired, first out, gives priority to stock with the earliest applicable expiration date.
Those rules can produce different picking sequences. A delivery received today could expire sooner than one that arrived three weeks ago.
Holds and customer requirements still apply. If a customer needs six months of remaining shelf life, a lot with only two months left should not be selected for that order.
What to Check in a WMS for Lot Tracking
Ask to see a realistic transaction sequence during a software demonstration. Receive two lots of the same SKU, split one across locations, ship part of it, and place the remainder on hold.
Then retrieve the receipt, current balances, movements, and affected shipments. Check what happens when a picker changes lots, a return arrives without readable identification, or a count finds the correct SKU total but the wrong lot split.
For a 3PL, repeat the search with matching codes under different clients.
Fulfillor’s inventory management software includes batch, lot, and expiry tracking from receiving through dispatch. Use your own warehouse scenario in a walkthrough to confirm how the required transactions, reports, and exceptions would be handled.
Check Whether Your Lot Records Work
Pick a lot that has been through several warehouse transactions. Ask someone who did not receive it to find its receipt, current balance, location changes, adjustments, and any outbound shipments.
Note where the search stalls. A missing transfer, an unexplained adjustment, or an unidentified return gives the team a specific problem to resolve. Assign each issue to the person responsible for checking it.
The next time a client asks about a lot, staff should be able to follow its history without relying on someone’s memory. That is the practical test of whether your warehouse lot tracking process works.
Frequently Asked Questions
Can different lots be stored in the same bin?
Yes, if staff can reliably identify each lot and the records maintain separate quantities. Separate storage may be more appropriate when labels, packaging, or handling requirements make mixed storage difficult to control.
Can a spreadsheet be used for lot tracking?
Yes, for a simple operation with controlled updates. It needs a transaction history connecting receipts, movements, adjustments, and shipments. A sheet showing only current balances cannot explain where shipped stock went.
Does every product need lot tracking?
No. The decision depends on product risks, client requirements, and applicable obligations. It is particularly useful where quality issues, shelf life, or supplier investigations affect groups of products.
Does lot tracking alone establish compliance?
No. It supports traceability, but compliance may also depend on product-specific identification, handling, validation, reporting, and record-retention requirements.