What Is a Lot Number? 5 Real Examples, Decoded

What Is a Lot Number?

A lot number (also called a lot code) is a unique identifier a manufacturer or distributor assigns to a specific quantity of product made or received under identical conditions: from one set of materials, in one time window. It lets teams trace, rotate, hold or recall that exact group of goods.

The code identifies a group, not a single unit. Every can, bottle or carton from that group carries it. If a quality issue turns up in one unit, the code tells you which other units were made alongside it and where they went.

US regulation uses similar language. FDA's pharmaceutical CGMP rules (21 CFR 210.3) describe a lot, control or batch number as a distinctive combination of letters, numbers or symbols from which the complete history of a batch or lot can be determined. That idea, a code that opens up a product's history, applies across industries.

This page covers what the code is and what it looks like. For tracing lots forward and backward through your supply chain, see our comprehensive guide to lot traceability.

How a Lot Is Formed

Units belong to one lot when they share every condition that could affect quality or safety. Common boundaries include:

• Production run: one line, one shift or one continuous run
• Inputs: identical ingredient lots, raw materials or components
• Time window: a single day, shift or batch cycle
• Receipt: for distributors, one inbound shipment of one item from one supplier lot

When any of those conditions changes (a new ingredient lot, a line changeover, a new day), most operations start a new lot. Smaller lots mean narrower recalls but more codes to manage. Larger lots mean fewer codes and broader exposure when something goes wrong.

Why Manufacturers and Distributors Assign Lot Numbers

A lot identifier follows each group of product through storage, picking and shipping. Operations teams rely on it to:

• Link finished goods to the ingredients, components and conditions used to make them
• Tie inventory to an expiration or best-by date for rotation
• Place suspect product on hold without freezing the entire SKU
• Identify which customers received a specific lot during a recall
• Answer customer, auditor and regulator questions with records instead of guesswork

Without one, a problem with a single production run can force you to treat every unit of that item as suspect.

Supplier-Assigned Lot vs Internal Lot

A supplier-assigned lot is printed by the manufacturer or vendor that produced the goods. An internal lot is assigned by your own facility, either when you produce something or when you receive goods and want your own identifier.

Many operations record both. The supplier's code preserves the link back to the source, which matters if that vendor issues a recall. The internal code can reflect your receipt date, plant or process in a format your team and systems already understand. What matters is cross-referencing the two so either one can find the other.

Regulatory Context: FSMA 204, DSCSA and GS1

Several frameworks shape how these codes are used in practice:

• FSMA Section 204 (Food Traceability Rule): For foods on FDA's Food Traceability List, firms must keep key data elements tied to a traceability lot code at critical tracking events such as receiving, transformation and shipping. Check FDA's site for the current compliance date.
• DSCSA (pharma): Prescription drug packages carry a product identifier that includes the lot and expiration date alongside the product code and serial number.
• GS1 standards: GS1 defines how batch/lot and expiration data are encoded in barcodes so trading partners can read them consistently.

Requirements vary by product and role, so confirm obligations with your compliance team and the source regulations.

Example of Lot Number Formats, Decoded

No universal format exists. Each manufacturer picks its own structure, so a lot code on a pallet of sauce looks nothing like one on a carton of tablets. Most codes are assembled from the same parts: dates, plant or line identifiers, shift codes, formula codes and sequential counters. The examples below are hypothetical but follow common industry patterns. Once you can read these building blocks, you can decode most codes that arrive at your dock and know what to ask a supplier when a format is unclear.

Food: Date + Line + Shift Code (L240915-A2)

A common food-plant pattern combines the production date with where and when the product was made. Read left to right:

• L: a prefix that marks the string as a lot rather than an item number
• 24: the year, 2024
• 09: the month, September
• 15: the day of the month
• A: production line A
• 2: second shift

Read together, L240915-A2 points to product made on Line A during second shift on September 15, 2024. The hyphen only aids readability. Date order varies by plant (YYMMDD, DDMMYY, MMDDYY), so confirm each supplier's convention instead of guessing. A string that is obvious under one convention can turn into a plausible but wrong date under another, which is worse than an impossible one because nobody questions it.

Julian Date Code (25015)

Julian codes are common in food and beverage because they fit in a tiny print area.

• 25: year of production, 2025
• 015: day 15 of the year, which is January 15

These ordinal date codes are compact and easy to print but hard to read at a glance. That is why warehouses often store a converted calendar date beside them. Variants include a one-digit year (5015) or a line suffix (25015-3). A single-digit year repeats every decade, so it suits products whose shelf life is far shorter than ten years.

Pharma Alphanumeric Lot (A2410037)

Pharmaceutical lots are often alphanumeric strings tied to batch manufacturing records.

• A: manufacturing site A
• 24: year of manufacture
• 10: October
• 037: the 37th batch made that month

So A2410037 is the 37th batch from Site A in October 2024. Each pharma lot ties back to a batch record documenting materials, equipment and test results. Under DSCSA it also appears with the product identifier, serial number and expiration date, which our drug serialization guide covers in depth.

Nutraceutical Blend Lot (VD3-2503-B12)

Supplement makers often build the formula into the code because one blend may feed several packaging runs.

• VD3: vitamin D3 formula
• 2503: blended in March 2025
• B12: twelfth blend batch of that month

One blend often fills several pack sizes, so 60-count and 120-count bottles may both carry VD3-2503-B12. The lot, not the SKU, becomes the right unit for holds and investigations. If a lab flags a potency problem, quality can block both bottle sizes in one action instead of hunting through two item records.

Consumer Goods Supplier Lot (CN4-2438-07)

Consumer goods distributors frequently receive supplier codes built on week-based dates.

• CN4: the supplier's Plant 4
• 24: 2024
• 38: week 38
• 07: the seventh run in that week

Non-perishables may lack an expiration date, yet CN4-2438-07 still matters for defect claims, supplier chargebacks and safety recalls. Suppliers also differ on how they count week 1 of a year, so record which calendar each one follows.

Supplier Lot vs Internal Lot on the Same Pallet

Say a pallet of tomato paste arrives with supplier lot 25015, and your dock assigns internal lot R250120-01 (first receipt of that item on January 20, 2025). The supplier's code links to their production records and any recall they issue. Yours links to your receipt, storage location and later use. If the paste goes into your finished sauce, the sauce gets a new lot tied back to both. A third-party logistics provider storing goods for many clients manages the same pairing for every owner. A WMS that records both codes at receiving can start that cross-reference the moment goods hit the dock, so a single lookup later answers where supplier lot 25015 ended up.

How to Build a Lot Numbering Scheme

If you assign your own lots, choose a structure deliberately. Common approaches include:

• Sequential (000101, 000102): unique, but meaningless without a system lookup.
• Date-based (YYMMDD or Julian): readable and sortable; add a suffix for multiple lots per day.
• Plant/line/shift codes: record where and when, helpful for multi-site operations.
• Supplier-based: keep the supplier's code as the primary ID, accepting formats you do not control.

Whatever you choose, keep codes short enough to print on small packs and avoid look-alike characters (O/0, I/1). Hold length and date order constant across sites, never reuse a code during the product's life and document the format for new staff and auditors.

Lot Number vs Batch Number vs Serial Number vs SKU vs Expiration Date

These five identifiers often sit side by side on one case or pallet label, which is exactly why people mix them up. Each one answers its own question: what product is this, which group did it come from, which individual unit is it, and how long will it stay usable?

• Lot number (lot code): a group of units sharing production or receipt conditions. It spans many units and supports traceability, holds, recalls and rotation. Example: L240915-A2.
• Batch number: a quantity produced in one process cycle, often a synonym for lot. It also covers multiple units and shows up in production records and quality release. Example: A2410037.
• Serial number: one individual unit. It supports item-level tracking, warranty work and pharma serialization. Example: SN 0004817726.
• SKU: a product type or variant, covering all units of that product. It drives ordering, pricing, slotting and replenishment. Example: SAUCE-TOM-16OZ.
• Expiration date: the end of usable shelf life, usually shared across a lot. It drives FEFO picking and expiration holds. Example: 2026-03-15.

Put simply, the SKU says what you have, the lot code says which production group it belongs to, a serial says which exact unit you are holding, and the expiration date says when it must be used or shipped. A WMS typically stores the SKU as the item master record and attaches the other three as attributes of each inventory record, as covered in our guide to inventory management in a warehouse.

When Lot and Batch Mean the Same Thing

Plenty of warehouses treat the two terms as interchangeable, and that rarely causes trouble. Where a distinction does exist, a batch usually means one production cycle, such as a single mixing tank, while a lot can be that whole batch or an identified portion of it. The FDA's current good manufacturing practice definitions for drugs follow this logic, describing a lot as a batch or a specific identified portion of a batch.

Here is how that plays out: a 5,000-liter beverage batch gets filled on two lines, producing two lots from one batch. If your plant works this way, document the rule and make sure your system captures both identifiers. If it does not, choose one term and apply it consistently across labels, scanner screens and reports.

When Item-Level Serialization Applies

Lots track groups; serials track individual units. Some products need both.

Prescription drugs are the clearest case. Under DSCSA, each saleable package carries a product identifier made up of the product code, a unique serial number, the lot and the expiration date. The lot still drives holds and recalls, while the serial supports package-level verification. High-value equipment, medical devices and some electronics are serialized too, mainly for warranty claims and service history. ASC Software's inventory management supports lot and serial number tracking, so both identifiers can be recorded against the same stock when a product calls for it.

Food, nutraceutical and most consumer goods operations usually stop at lot-level tracking. For pharma specifics, see our comprehensive guide to drug serialization.

Where Lot Numbers Are Printed: Unit Labels, Cases and Pallets

A lot code only helps if people and scanners can find it. The same code appears at several packaging levels, and each one does a different job: the unit label supports the end user and quality team, the case label supports picking and shipping, and the pallet label supports receiving and putaway.

Consistency across those levels matters. If the unit reads L240915-A2 but the case shows another format, receivers end up guessing. Printing the code as both human-readable text and a barcode at every level lets staff capture it quickly each time the product is handled. Our guide to warehouse labels covers label design in more depth.

Primary Packaging and Unit Labels

On the unit, an inkjet, laser or thermal printer marks the code on a can end, bottle neck, cap, pouch seal or carton flap, often beside the expiration or best-by date. Space is tight, so short formats such as Julian codes are common here. Prescription drug packages also carry a 2D barcode that combines the product identifier, serial number, lot and expiry, as explained in our overview of drug serialization.

Case Labels

Case labels repeat the code in a larger, scanner-friendly layout, usually next to the product code, quantity and expiration date. Pickers work mostly at this level, so readable text and a clean barcode reduce mis-picks and support accurate capture at shipping. When a case holds a single lot, its label should match every unit inside.

Pallet Labels and Shipping Documents

Pallet labels usually carry a unique identifier such as a GS1 Serial Shipping Container Code (SSCC), plus product, quantity, batch and use-by date for single-lot pallets. Shipping documents and advance ship notices (ASNs) list the lots on each load so the receiver knows what to expect.

Mixed-lot pallets are common at line changeovers and in distribution. Here the pallet label may not show one lot, so the detail lives on the cases and in the shipping record. Scanning each case during check-in keeps a mixed pallet from being recorded as a single lot.

How GS1-128 Barcodes Encode Lot and Expiration Data

GS1-128 is a widely used symbology for logistics labels. It stores data in fields marked by Application Identifiers (AIs), short numeric prefixes that tell the scanner what each value means. Common ones in the GS1 standard include:

• (00) SSCC, the pallet or logistics unit identifier
• (01) GTIN, the product identifier
• (10) Batch or lot identifier
• (17) Expiration date in YYMMDD format

One scan can capture product, lot and shelf-life date together, which removes manual keying. The text below the barcode shows the same values with the AIs in parentheses.

Capturing the Lot Number at Receiving

Receiving is where the code enters your system, and every downstream process depends on getting it right there. A WMS can prompt the receiver to scan or key in the lot plus its expiration, check both against the ASN, and tie them to the received quantity and putaway location. It can also refuse to close a receipt until a lot is recorded for every lot-controlled item, which stops blank fields from slipping into stock. For more on how inbound work is handled, see the receiving features page.

If the code is wrong at the dock, FEFO picking, expiration holds and recall lookups all run on bad data. Accurate batch and expiry records also feed shelf-life-aware planning, which our guide to forecasting demand covers.

How Lot Numbers Drive FEFO, Expiration Control, Quality Holds and Recalls

Once a lot is captured and tied to an expiration date and a storage location, it becomes the key that operational rules act on. Rather than treating every unit of a SKU as interchangeable, a system can direct, block or find inventory one lot at a time.

Four everyday uses follow. The process detail is kept short on purpose; step-by-step forward and backward tracing lives in the traceability guide linked earlier in this article.

FEFO Picking

First Expired, First Out (FEFO) sends pickers to the lot with the earliest expiration date first, regardless of when it arrived at the dock. That only works when each unit links to a lot and each lot links to a date. With those links in place, warehouse software can point every picker to the correct lot and bin, then flag a scan of a later-dated lot as an exception before it ships.

For goods without dates, many operations apply FIFO by receipt date, still using the lot as the reference. Food plants often run both methods side by side, depending on the product, which our food and beverage software page discusses. Our FEFO inventory management guide covers the method in depth.

Expiration Monitoring

Because the expiration date usually belongs to the lot rather than the SKU, monitoring at that level shows exactly how much stock is nearing its date and where it sits. Software can alert teams when a lot crosses a set threshold, block lots that fall below a customer's minimum remaining shelf life and move expired stock into a hold status. Our article on building an expiration date tracker explains how to set those thresholds and alerts. Pharmaceutical distributors face especially tight dating requirements, a topic covered in our guide to pharma warehouse management systems.

Quality Holds

When quality assurance has a question about a production run, such as a pending lab result, a supplier notice or a temperature excursion, that lot can be placed on hold. Held stock stays in inventory but is blocked from picking and shipping until someone releases or rejects it.

Holding by lot code brings precision. Other lots of the same item keep moving, so one suspect run does not stop all fulfillment. A WMS can also log the hold reason and the person who released it, giving auditors a clear trail.

Recalls

During a recall, the lot number narrows the problem from "every unit of this product" to "these specific lots." One lookup can reveal how much of the affected lot remains on hand, which locations hold it and which customers received it, on which orders and dates.

That is the difference between contacting everyone who bought the SKU and contacting only those who received the suspect product. ASC's recall features provide chain-of-custody visibility using lot codes, license numbers or serial numbers, and recall reports include lot history.

Managing Lot Numbers With ASC Software

Defining what a lot is takes a paragraph. The harder work is capturing that identifier correctly at every touchpoint, then acting on it when an order is picked, a pallet goes on hold or a supplier calls about a recall. Gaps tend to appear here, whether the record lives in a spreadsheet, a paper receiving log or a system that treats the lot field as optional free text anyone can skip.

If you are weighing whether your current setup can keep pace, here is how ASC Software supports lot-controlled operations, based on the descriptions on its own feature and industry pages:

• Receiving: According to the receiving features, every received item can be tagged with its batch or lot number, giving traceability from storage to shipping. Lot data is captured at the receiving step, so the identifier enters the system before the product reaches a rack location.
• Inventory management: Lot and serial tracking is supported in inventory management. This matters when the same SKU arrives under several different lot codes in a single week and each one needs to stay distinct on the shelf.
• Food and beverage: The food and beverage software page describes configurable rules for lot and expiration dates with FEFO and FIFO, along with forward and reverse lot traceability through the Production Work Orders app. That pairing is what manufacturers look for when a raw ingredient has to be tied to the finished goods it went into.
• Distribution: For distributors, the platform offers GS1 bar code automation for lot and expiration date. When supplier cases already carry GS1 bar codes, scanning replaces the manual keying that causes so many transposed digits at the dock.
• Recalls: The recalls feature provides chain-of-custody visibility using lot codes, license numbers or serial numbers, and recall reports include lot history.

Feature lists only tell part of the story. A practical way to test any warehouse system, this one included, is to follow a single real lot from start to finish:

1. Receive it and confirm the code is recorded at the dock, not added later.
2. Put it away and check that its location is tied to that code.
3. Pick it by expiration date and see whether the system directs the right lot or leaves the choice to the picker.
4. Place it on quality hold and try to allocate it to an order. The system should block the pick.
5. Run a recall lookup and see how quickly you can answer where that lot came from and where it went.

If every step pulls from the same lot record rather than a copy someone retyped, your lot data is doing its job. If one step forces a workaround, such as a side spreadsheet, a sticky note on the rack or a supervisor override, that is the weak point to fix before an auditor or a customer finds it for you.

Request a Demo to see one lot move from receiving through recall reporting in ASC Software.