What is a batch number?
A batch number is a unique code of digits and/or letters that identifies a defined quantity of product made in a single production run under the same conditions, so that the complete manufacturing and distribution history of that quantity can be traced. The same identifier is also called a lot number or simply LOT, and GS1 carries it as AI (10) batch/lot. The batch number appears on packaging and labels, and in the plant’s systems it is linked to raw materials, recipe, process data and quality results. When a complaint or recall occurs, the batch number determines which products are affected, and which are not. It is a legal requirement for food, medicines and cosmetics, and medical devices must carry a lot or serial number.
A batch number links a physical group of products to all the data about how, when and from what that group was made.
🧠 What is the difference between batch, lot and batch number?
In practice batch and lot are often used interchangeably, but regulations sometimes draw a fine distinction:
- Batch - under the US GMP rules (21 CFR 210.3), a specific quantity intended to have uniform character and quality within specified limits, produced according to a single manufacturing order during the same cycle of manufacture.
- Lot - a batch, or a specific identified portion of a batch. In continuous production, a lot is an amount defined by a unit of time or quantity.
- Batch number (lot number) - any distinctive combination of letters, numbers or symbols from which the complete history of manufacture, processing, packing, holding and distribution can be determined.
EU food law (Directive 2011/91/EU) uses the term lot: sales units produced, manufactured or packaged under practically the same conditions. For anyone designing a system the essence is the same everywhere: one number, one homogeneous group, one traceable history.
🎯 Why are batch numbers important?
| Use case | What the batch number makes possible |
|---|---|
| Traceability | After an incident, tracing which raw materials, machines and process data belong to a product |
| Targeted recall | Recalling only the affected batches instead of an entire product line |
| Quality control | Recording samples, lab results and deviations per batch, then releasing or rejecting the batch |
| Compliance and audit | Demonstrating conformity with GMP, HACCP, ISO 9001 and FDA requirements |
| Production repeatability | Reusing the same recipe settings through MES or batch control |
| Root cause investigation | Comparing batches after complaints as part of a root cause analysis |
🔢 What does a batch number look like?
There is no globally prescribed format; every manufacturer chooses its own scheme. Common building blocks
are the date, production line, shift and a sequence number. A fictitious example such as L26293-03 would then mean: prefix L, year 2026, day 293 and the third batch of that day. Date
codes made of year plus day number (Julian date) are common in the food industry.
| Sector | Example (fictitious) | Structure |
|---|---|---|
| Pharmaceutical tablets | BTCH20250725A |
Production date + shift code |
| Food products (sauce) | L202507-02 |
Prefix L + year/month + batch sequence number |
| Paint production | VP-0701-003 |
Plant code + week + batch |
| Recipe-driven batch process | Generated by the batch system | Assigned when the control recipe is created under ISA-88 |
The batch number is unique per batch, not per product. To identify one individual item, you use a serial number.
🏷️ How is a batch number encoded under GS1?
In the supply chain the batch number is usually carried in a barcode according to GS1 standards. The data element is Application Identifier (AI) 10:
| GS1 AI | Data | Format |
|---|---|---|
| (01) | Product code (GTIN) | 14 digits |
| (10) | Batch or lot number | Alphanumeric, up to 20 characters, variable length |
| (17) | Expiry date | YYMMDD |
| (21) | Serial number | Alphanumeric, up to 20 characters |
Because AI (10) has a variable length, it is followed by a separator (FNC1) unless it is the last element in the symbol. The batch number is not part of the unique product identification: that remains the GTIN. These elements are printed in a GS1-128 barcode on cases and pallets, or in a DataMatrix on smaller packs. For medical devices the batch number forms part of the production identifier in the UDI.
🔤 Why does a pack say LOT, L or Ch.-B.?
The label in front of the number depends on the sector and the language. Its meaning is always the same: the manufacturer’s lot number.
| Marking | Where you see it | Background |
|---|---|---|
| L | Prepacked food | Directive 2011/91/EU: the lot marking starts with L unless it is clearly distinguishable |
| LOT in a box | Medical devices and IVDs | Symbol 5.1.5 “batch code” from ISO 15223-1 |
| BATCH/LOT | Human-readable text under a GS1 barcode | Official data title of GS1 AI (10) |
| Ch.-B. | German-language packs, especially medicines | Short for Chargenbezeichnung |
| Lot / Batch | General labels | Free text chosen by the manufacturer |
The lot number only tells you which group of products an item belongs to. The other codes on the same pack each have their own role:
| Code | What it identifies |
|---|---|
| Batch or lot number | A group of identical products from one production run |
| Serial Number | One individual item |
| SSCC | One logistic unit, such as a case or pallet |
| UDI-PI | The production identifier of a medical device: lot, serial number and dates |
⚖️ Which rules apply to batch numbers in the EU and the US?
- Food - Directive 2011/91/EU requires a lot marking, preceded by the letter L unless it is clearly distinguishable. It may be omitted when the date of minimum durability or use-by date shows at least the uncoded day and month. Regulation (EC) 178/2002 has required businesses since 2005 to trace one step back (supplier) and one step forward (customer).
- Medicines - Directive 2001/83/EC requires the manufacturer’s batch number on the outer packaging. Since 9 February 2019 the unique identifier under the EU Falsified Medicines Directive (Delegated Regulation (EU) 2016/161) contains product code, serial number, batch number and expiry date in a 2D Data Matrix; in the Netherlands verification runs through NMVO.
- Medical devices - the MDR (Regulation (EU) 2017/745) requires a lot or serial number on the label; the lot number is part of the production identifier in the UDI.
- Cosmetics - Regulation (EC) 1223/2009 requires the batch number or a reference identifying the batch on the packaging.
- Retention periods - under the EU GMP Guide you keep batch documentation for at least one year after expiry or five years after certification by the Qualified Person, whichever is longer. In the US the minimum is one year after the expiry date (21 CFR 211.180).
- Quality management - ISO 9001 requires identification and traceability of outputs whenever traceability is a requirement (clause 8.5.2).
In the Netherlands, the NVWA supervises food recalls and the IGJ supervises medicines and medical devices.
🔧 How does a batch number flow through the IT and OT layers?
A batch number only delivers value when it is identical in every layer of the ISA-95 pyramid:
- ERP creates the production order and records incoming raw material batches from suppliers.
- MES or the batch system assigns the batch number, links it to the recipe and records the genealogy: which raw material batches went into which finished product batch.
- PLC and SCADA execute the batch; the historian stores process data with the batch number as context.
- Label printer or inkjet coder prints the number; a camera with machine vision checks that the print is legible and correct.
- LIMS links laboratory results to the batch, after which quality assurance releases it.
- WMS follows the batch through the warehouse, so that during a recall you know where the stock is.
This creates end-to-end tracking and tracing from supplier to customer.
🛠️ How do you set up a batch numbering system?
- Define the batch boundary - decide what one batch is: one vessel fill, one shift, or a fixed time unit in continuous processes (see Discrete, Batch and Continuous Processes). The smaller the batch, the smaller a recall, but the heavier the administration.
- Keep the number short and unambiguous - GS1 allows up to 20 alphanumeric characters, but a shorter number keeps the barcode compact and reduces errors during manual entry. Avoid confusable characters such as O/0 and I/1.
- Let one system issue numbers - duplicate numbers issued by both ERP and MES undermine traceability.
- Safeguard data integrity - pharmaceutical batch records fall under 21 CFR Part 11 and EU GMP Annex 11, with audit trails and electronic signatures; validate the systems according to GAMP.
- Test traceability - run a mock recall periodically: start from one raw material batch, find all customers, and check the mass balance.
🔁 What is the difference between a batch number and a serial number?
| Characteristic | Batch number | Serial Number |
|---|---|---|
| Identifies | A group of products from one run | One individual item |
| Typical use | Food, pharma, chemicals, paint, components | Machines, electronics, medical equipment, medicine packs |
| Recall granularity | Per batch | Per item |
| Important for | Quality, release and recall | Maintenance, warranty, asset tracking and authenticity checks |
Both can occur together: a medicine pack carries both a batch number and a unique serial number.
❓ Frequently asked questions
Is a batch number the same as a lot number?
In practice batch number, lot number and LOT are used as synonyms, including in the GS1 standard, which has one field for both: AI (10) batch/lot. The US GMP rules do draw a distinction: a lot can also be a portion of a batch, or in continuous production an amount produced per unit of time.
Where do I find the batch number on a package?
The batch number is usually printed near the expiry or best-before date, often preceded by “L”, “Lot”, “Batch” or “Ch.-B.”. On medicines and many logistics packs the batch number is also encoded in a Data Matrix or GS1-128 barcode after AI (10).
How long can a batch number be under GS1?
Under GS1, a batch number in Application Identifier (10) is alphanumeric and at most 20 characters long. Because the field has a variable length, it is followed by an FNC1 separator whenever another data element comes after it.
Is a batch number a legal requirement?
A batch number is legally required for, among others, prepacked food (unless an uncoded date with day and month is sufficient), medicines and cosmetics; medical devices must carry a lot or serial number. For other products a batch number is not always mandatory, but it is needed to meet traceability requirements from ISO 9001 or customer contracts.
Who assigns the batch number in a factory?
In an automated plant, the MES or the batch system usually assigns the batch number when the production order starts. The ERP system records the batch numbers of incoming raw materials, so that the genealogy from raw material to finished product is complete.
How long must batch records be kept?
For medicines in the EU, batch records must be kept for at least one year after expiry or five years after release by the Qualified Person, whichever is longer. In the US, drug batch records must be kept for at least one year after the expiry date of the batch.
📌 In summary
A batch number identifies a homogeneous production batch and enables traceability, targeted recalls, quality release and compliance.
The number is encoded under GS1 AI (10), is mandatory in food and pharma, and connects ERP, MES, PLC, LIMS and WMS into one complete product history.