What Is a Lot Number? Examples and Lot Tracking in a WMS

What Is a Lot Number?

In plain terms, the lot number printed on a package is an identifier given to a quantity of product that was made, processed or received together and is expected to be uniform. Every unit in that group shares the same raw materials, equipment, time window and production conditions, so the whole quantity can be managed as a single block of inventory.

A helpful way to picture it: a lot code works like a family name. The SKU tells you what the item is, such as a 12-ounce jar of salsa. The lot tells you which run it came from, such as the jars filled on Line 2 on a Tuesday morning. That second layer of detail lets a business run a targeted recall, control expiry dates or place a quality hold without pulling every jar of that salsa off the shelf.

Who assigns lot numbers?

Usually the manufacturer or co-packer creates the code at the point of production. Processors and repackers may issue a new one when they transform or combine product, for example blending ingredients into a new formula or breaking bulk drums down into retail bottles.

Warehouses and 3PLs sometimes create internal lot codes as well. Common reasons include a supplier label that is missing or unreadable, goods arriving with no lot marking at all, or a business choosing to group inbound stock by receipt date. Whenever a facility assigns its own code, it should record the original supplier lot alongside it. Without that link, the trail back to the producer breaks, and the internal code becomes far less useful during an investigation.

Why do lot numbers matter?

They connect a physical product to its history. A lot identifier supports:

• Traceability: knowing where a lot originated and every customer or location it shipped to.
• Recalls: isolating only the affected run instead of an entire product line.
• Expiry and shelf-life management: tracking dates that apply to everything produced together.
• Quality holds: freezing a suspect lot while samples are tested.
• Compliance: meeting record-keeping requirements in regulated industries and answering customer audits with documented evidence.

Without the code, each of these tasks falls back on guesswork or broad, expensive action, like quarantining all stock of an item when only one production day was affected.

Where does the lot number appear on packaging?

Look for markings such as LOT, Lot No., L or Batch. Medical device labels often use a standard symbol: a box containing the word LOT. The code is usually printed or inkjet-coded close to the expiration or best-by date. Typical spots include the bottom of cans, the crimped end of tubes, the side panel of cartons, and labels on shipping cases and pallets. On those larger units, the same value is often encoded in a barcode in addition to human-readable text, so receiving staff can scan it rather than key it in by hand.

How Do You Read a Lot Number? Common Formats Decoded

No universal format exists. Every manufacturer sets its own scheme, so receiving staff regularly face codes that look like random strings of characters. Underneath, most are assembled from a few predictable pieces: a date, a plant or line, a shift and a sequence number.

Once you recognize those pieces, most supplier labels become readable. Start by finding the date, then work out how it is written, then identify what the leftover characters stand for. If a code still doesn't make sense, ask the supplier for their lot code key and keep a copy at the receiving desk.

What are the most common lot number formats?

• Date-based codes: embed the production date, often as YYMMDD (240315 for March 15, 2024).
• Julian date codes: combine the year with the day of the year (001 to 365, or 366 in leap years). 24075 means day 75 of 2024.
• Sequential codes: a running count such as 000457 that increases with each new lot.
• Plant, line and shift codes: identify the facility, production line and shift, often paired with a sequence or date.

Real-world codes frequently mix two or more of these, sometimes with a prefix like L or LOT.

How do you decode a sample lot code segment by segment?

GS1-128 is a barcode symbology printed on cases and pallets. It encodes data with Application Identifiers (AIs), short numeric prefixes shown in parentheses, and GS1 publishes the full list. AI (10) carries the batch or lot, while AI (17) holds the expiry as YYMMDD.

Here are four sample codes broken into their parts:

• L240315-A2: splits into L, 240315, A and 2. The L is a lot prefix, 240315 means produced March 15, 2024, A marks the shift and 2 marks the line.
• 24075: splits into 24 and 075, meaning the year 2024 and its 75th day, which is the same calendar date as the first sample.
• P2-L3-S1-0457: reads as Plant 2, Line 3, Shift 1, and the 457th lot in that plant's sequence.
• (01)00614141999996(17)260630(10)L240315-A2: a full GS1-128 string. The (01) segment holds the GTIN of the trade item, (17) shows an expiry of June 30, 2026, and (10) carries lot L240315-A2.

The first two samples describe one production day written two different ways. Because the value after (10) can vary in length, it usually sits at the end of a GS1-128 string.

How do expiration and best-by dates appear alongside lot numbers?

Expiration, use-by and best-by dates typically print beside the lot identifier under labels such as EXP, Use By, BB or Best Before. Slash formats can mislead: 03/04/25 might be March 4 or April 3. GS1 barcodes remove that doubt because the (17) field is always YYMMDD. At the dock, record lot and expiry as two separate fields instead of folding the date into the code. In Sphere WMS, lot control at the dock tracks expiry dates next to each lot, so both values stay tied to the physical stock.

How should you design an internal lot numbering scheme?

If you assign your own lots, a simple template works well:

[Prefix]-[YYMMDD or Julian date]-[Site/Line]-[Sequence], for example R-240315-DC1-003

Best practices:

• Keep length and segment order consistent.
• Make it scannable by printing a barcode, ideally GS1-128 with AI (10).
• Avoid look-alike characters such as O vs. 0 and I vs. 1.
• Leave out details that may change, such as a customer name.
• Always link each internal lot back to the supplier's original one.

Write the scheme down, train receivers on it and post the key near label printers so new hires decode internal lots the same way experienced staff do. A consistent pattern pays off downstream. Pickers can confirm the right lot by scan during wave picking, and a WMS can then split stock into separate records by location, lot, pallet and serial, which the inventory management page describes in more detail.

What Does an Example of Lot Number Look Like in Each Industry?

Every regulated sector relies on lot codes, but the format, placement and governing rules differ from one to the next. The list below shows a realistic style for each industry and where you would typically find it. These examples are illustrative and not taken from specific brands.

• Food and beverage, 24075B2: printed on a can end, bottle neck or carton side near the best-by date, and repeated on the case label.
• Pharmaceuticals, LOT A24C015 EXP 2026-03: found on the carton flap and encoded in a 2D Data Matrix barcode alongside the NDC, serial and expiry.
• Medical devices, LOT 2403150457: shown beside the LOT symbol on the device label and package, and built into the UDI barcode.
• Cosmetics, 4075L1: stamped into the crimp of a tube, on the bottom of a jar or on the outer carton.
• Chemicals, 24-0315-R07: listed on the drum or pail label, the certificate of analysis and shipping papers.
• Electronics, Lot 4D2215, D/C 2411: printed on reel labels and component packaging, often next to a YYWW date code.

How do lot numbers work in food and beverage under FSMA 204?

The FDA's Food Traceability Rule (FSMA Section 204) covers foods on the Food Traceability List, including leafy greens, shell eggs and certain seafood. For these items, a traceability lot code (TLC) must be assigned at defined points and recorded alongside Key Data Elements (KDEs), such as quantity, location and dates, at each Critical Tracking Event (CTE), such as receiving, shipping and transformation. When the FDA asks, covered firms have 24 hours to hand over records, sometimes as an electronic sortable spreadsheet. The compliance date has been pushed back, so check the current deadline with the FDA before planning around it.

How are lot numbers used in pharmaceuticals under DSCSA?

Under the Drug Supply Chain Security Act (DSCSA), every prescription drug package carries a product identifier made up of four elements: the National Drug Code (NDC), a unique serial number, the lot and the expiration date. Each appears in human-readable text and inside a 2D Data Matrix barcode. Trading partners pass this lot data along in their transaction information, so a warehouse handling these drugs has to capture lot and expiry correctly as soon as cartons arrive. Sphere WMS records expiry dates with each lot as goods are logged at inbound receiving, which turns that capture into part of the normal dock routine.

How do lot numbers fit into medical device UDI?

Most devices must carry a UDI under the FDA's Unique Device Identification system, and it has two parts. The device identifier (DI) points to the model and labeler. The production identifier (PI) holds variable data, such as lot or batch, serial number, expiration date and manufacture date, whenever those appear on the label. In GS1 barcodes, the lot is encoded under Application Identifier (10), so scanners can pull it out automatically instead of relying on someone to type it.

What do lot numbers look like in cosmetics, chemicals and electronics?

• Cosmetics: codes tend to be short, embossed or printed, and often built on a Julian date. Products sold in the EU must show a batch number or reference on the label under the EU Cosmetics Regulation.
• Chemicals: each drum or tote ties back to its certificate of analysis, which customers use for quality checks and shelf-life decisions. Whether a site rotates stock first in, first out or uses LIFO for valuation, the code on each drum keeps those certificates matched to the right containers.
• Electronics: components carry a lot code plus a date code, usually in YYWW (year and week) format, so defects or counterfeits can be traced to a single production run. Keeping reels from separate runs apart in the system is simpler when inventory segmentation includes lot and serial fields.

How Is a Lot Number Different From a Batch Number, Serial Number or SKU?

These four identifiers get mixed up because they often sit side by side on one label. What separates them is the thing each one points to and how narrow that target is.

• Lot: identifies a group of units produced or brought in as one quantity. Manufacturers, processors and warehouses all assign them. Granularity is the group, and typical uses are recalls, expiry control and quality holds.
• Batch: the output of one production run or recipe cycle, assigned by the manufacturer. It also works at group level and shows up most in process manufacturing, pharma and chemicals.
• Serial: points to one individual unit and comes from the manufacturer. It is the most granular identifier and supports warranty claims, returns, high-value assets and DSCSA.
• SKU: names a product type or variant and is set by the seller, distributor or warehouse. It sits at product level and drives ordering, stock counts and replenishment.

Think of them as nested layers. One SKU can span dozens of lots over a year, and one lot can hold thousands of individually serialized units. A WMS that records every layer lets you answer different questions from the same stock: how many cases of a product you own, which of those came from a suspect run, and where one particular unit ended up. When you compare platforms, check that the one you evaluate can capture each of these layers for the stock you handle; the inventory features page shows how Sphere segments inventory.

Are lot numbers and batch numbers the same thing?

For most day-to-day purposes, yes. Plenty of labels and standards use the terms interchangeably, and GS1 Application Identifier (10) covers both under a single "batch/lot" designation.

Some sectors do separate them. In process manufacturing and pharmaceuticals, a batch can mean the output of one recipe or mixing cycle, while a lot may combine several batches, or split one, into a quantity that is packaged and released together. Because definitions vary, confirm how each supplier uses the words before you map their codes into your system.

Is a lot number the same as a serial number?

No, and confusing the two causes real problems. All units in a group carry one shared lot code, whereas a serial is assigned to exactly one item. Recalling by lot pulls the whole group; a serial lets you locate one specific piece. Many regulated goods carry both identifiers, including drug packages covered by DSCSA and serialized medical devices. Deciding early which items need lot control, serial control or both is one of the setup choices covered in our article on avoiding pitfalls in rapid WMS implementations.

How do expiration and date codes relate to lot numbers?

An expiration date normally applies to the entire lot, because all of its units share a production date and identical conditions. Some manufacturers build the production date into the lot code itself, but that embedded date is not the expiry date. Keep them as separate data: record the lot identifier and the expiration date in their own fields so shelf-life rules and recall searches return accurate results. Sphere's lot control features keep expiry attached to each lot from the point of receipt onward.

How Does a WMS Track Lot Numbers From Receiving to Recall?

Reading a lot code is only half the job. The other half is keeping that code tied to a physical location and to every order it leaves on. Follow one hypothetical lot, L240315-A2, a pallet of 60 cases of packaged sauce expiring June 30, 2026, as it moves through the building.

What happens to a lot at receiving?

The receiver scans the GS1-128 pallet label. The system reads AI (01) for the product, AI (10) for the lot and AI (17) for the expiry date, then checks all three against the advance ship notice or purchase order. If the label is missing, the receiver keys the code in from a case and may assign an internal lot linked to the supplier's. Scanning instead of handwriting at this first step prevents most of the errors that surface later.

How is a lot put away, stored and placed on hold?

The pallet goes to a bin, and the system records quantity by bin, lot and pallet ID. If cases are broken out, each can carry its own case ID, and serialized items keep their serial numbers. If QA flags L240315-A2 for testing, a quality hold blocks it from picking until release, while other lots of the same SKU stay available.

How are lots picked and shipped?

Many warehouses ship the oldest received stock first (FIFO, first in, first out) or the nearest expiry first (FEFO, first expired, first out). Both are common industry practices for cutting spoilage and write-offs. Expiry-based rotation matters most for short-dated goods like dairy or sauces, where a lot that sits too long turns into a loss. At the pick face, the operator scans the bin and lot to confirm the right stock. At shipping, the lot is recorded against the order, customer and ship date.

How does a WMS trace a lot forward and backward in a recall?

Forward traceability follows a lot from your dock to every customer who received it. Backward traceability runs it back to the supplier, the receipt and the inbound shipment. Suppose the supplier recalls L240315-A2. Because the lot was captured at each step, you can find which bins still hold it, put that stock on hold, list every order it shipped on and pull the receiving record tied to the supplier's delivery. FSMA 204's 24-hour records request expects this kind of lookup for covered foods.

Why do spreadsheets and paper fall short?

Manual tracking breaks at the handoffs. Codes get mistyped, receiving logs aren't linked to bins, and picks are logged by SKU alone. Consider a distributor that keeps lots in a shared spreadsheet: if one receiver types L240315-A2 and another enters it with a letter O in place of the zero, a search for the recalled code quietly misses part of the stock. In a recall, teams end up searching files and walking aisles. They often pull more product than needed or miss shipments. Capturing lot data by scan in one system closes those gaps, and that is a core reason companies adopt a warehouse management system.

Where does Sphere WMS fit?

Sphere WMS includes lot control that tracks products grouped in lots, monitors goods by lot number with expiry date tracking and supports compliance with industry regulations. The receiving and putaway page covers how it works. Inventory can be segmented by bin location, lot number, pallet/case ID and serial number, as covered under inventory management. More broadly, any WMS you consider for lot tracking should be able to tie each lot to a place in the building and a quantity on hand, because that pairing is what makes the forward and backward lookups described earlier possible. Request a Demo to see Sphere WMS lot control in action.