What are lot numbers?
Definition
A lot number (also called a batch number, code number, or lot code) is a unique identifier assigned to a group of products or materials that were manufactured, processed, or received together under the same conditions. Every item within that batch shares the same lot number, allowing the entire group to be traced, recalled, or investigated as a unit.
In manufacturing, lot numbers are the backbone of traceability. They connect finished products back to the raw materials used to make them, the dates they were produced, the processes they went through, and the quality checks that were completed. Without lot numbers, you cannot answer the question every customer, regulator and quality manager eventually asks: "Which items are affected, and where did they go?"
Lot numbers are used across virtually every manufacturing sector — from food and pharmaceuticals to electronics, automotive components and specialist engineering. Wherever a group of products is made together and needs to be traced together, lot numbers are the mechanism that makes that tracing possible.
Are "lot number" and "batch number" the same thing?
Yes — completely interchangeable. Batch number, code number, lot code, and lot number all refer to the same concept: a unique identifier assigned to a group of products produced or received together. The terminology varies by industry and region, but the function is identical.
Real example
A London-based pharmaceutical manufacturer produces a batch of 500 units on 15 March 2024:
MED-20240315-001If a defect is discovered in one unit from this batch, every other unit in batch MED-20240315-001 can be immediately identified and recalled — regardless of where they've been shipped.
Lot numbers vs serial numbers vs SKUs
These three identifiers are often confused — and using the wrong one for the wrong purpose causes real problems. Here's exactly how they differ and when to use each:
| Identifier | Tracks | Uniqueness | Best used for | Example |
|---|---|---|---|---|
| Lot Number | A group/batch of items made together | One per batch — all items in the batch share it | Traceability, recalls, quality control, batch management | MED-20240315-001 |
| Serial Number | A single, individual item | Unique per unit — no two items share it | Warranty tracking, repair history, individual item lifecycle | SN-00194827 |
| SKU | A product type or variant | Shared by all items of the same type/variant | Inventory counts, pricing, product catalogues, ordering | SHIRT-BLU-M |
The practical rule: Use lot numbers when you need to track a batch. Use serial numbers when you need to track an individual item. Use SKUs when you need to track a product type. Many manufacturers use all three simultaneously — a product has a SKU (what it is), a lot number (when it was made), and a serial number (which individual unit it is).
Why lot numbers matter — and what happens without them
For manufacturers who've never implemented lot numbers, the system can seem like unnecessary overhead. Until something goes wrong. At that point, the absence of lot tracking transforms a manageable quality issue into an expensive, reputation-damaging nightmare.
Blanket recalls instead of targeted ones
Without lot numbers, a quality issue means recalling every product of that type ever shipped — not just the affected batch. A targeted recall becomes a total recall. The cost and reputational damage is multiplied many times over.
No root cause analysis
If you can't trace a defective product back to the materials, processes and people involved in making it, you can't find the root cause — and the same problem keeps recurring. Every quality investigation stalls at "we don't know which batch this came from."
Regulatory compliance failure
In sectors like food, pharmaceuticals, medical devices and cosmetics, lot number traceability is a legal requirement. Operating without it isn't just operationally risky — it can mean losing your licence to operate.
Inventory chaos at expiry
Products with expiry dates — ingredients, materials, finished goods — need to be used in the right order. Without lot tracking, FIFO (first in, first out) management is guesswork, and expired stock regularly ends up in production or shipments.
7×
Product recalls are estimated to cost businesses seven times more when items can't be specifically identified by lot — because a targeted recall becomes a complete withdrawal from all channels.
Which industries use lot numbers?
Lot numbers are used across a wide range of manufacturing sectors. Here are the most common — and what makes lot tracking particularly important in each:
Food & Beverage
Expiry dates, allergen tracking and food safety regulations make lot numbers legally mandatory. A contamination event requires immediate batch isolation.
Example: a London craft brewery tracking each batch of beer from grain to glass.
Pharmaceuticals
Regulatory bodies require complete end-to-end traceability. Every ingredient, every process, every quality check must be linked to a specific batch.
Example: tracking a medication batch from raw API to finished blister pack.
Cosmetics
EU and UK cosmetics regulations require lot traceability. Skin reactions or contamination events need rapid batch isolation across all sales channels.
Example: tracking a skincare product batch from raw ingredient to retail shelf.
Electronics
Component batches from specific suppliers can have hidden defects. Lot tracking connects finished product failures back to the specific supplier batch that caused them.
Example: isolating a faulty capacitor batch across hundreds of assembled PCBs.
Specialist manufacturing
For custom-engineered components, marine equipment and bespoke products, lot numbers provide the traceability that quality standards and customer contracts require.
Example: Reef Zlements tracking custom marine product batches with Brytebuild.
Automotive parts
Safety-critical components require complete traceability. A single batch of faulty brake components needs to be traceable across every vehicle that received them.
Example: tracking a brake disc batch through supplier, production and distribution.
How to create an effective lot number system
There's no single "correct" format for a lot number — but effective lot numbers share three essential qualities: they're unique (no two batches share the same number), readable (your team can interpret what they mean), and consistent (the format never changes). Here's how to build a system that works:
Decide what information your lot numbers need to capture
At minimum, include the production date and a sequence number. For products with expiry, include the expiry date. For multi-location operations, include the site code. For regulated industries, include any mandatory fields.
Choose a clear, consistent format
Define the structure and stick to it. Use dates in ISO format (YYYYMMDD) to avoid ambiguity between UK and US date styles. Separate sections with a dash or underscore for readability. Document the format and make sure everyone follows it.
Assign lot numbers at the point of production or receipt
Lot numbers must be assigned before production begins or the moment goods are received into your warehouse — not retrospectively. Assign at the start, not the end. Use MRP software like Brytebuild to automate this and remove the risk of someone forgetting.
Record all critical information against the lot
Capture: production date and time, raw materials and their own lot numbers, who was involved, which work instructions were followed, which quality checks were completed, and the final quantities produced. The more complete the record, the more powerful the traceability.
Print and apply barcodes or QR codes
Lot numbers are only useful if they're scannable in the warehouse, on the production floor, and when goods leave your site. Barcode or QR labels make scanning fast and error-free. In Brytebuild, you can print lot number labels directly from the system.
Track lot numbers through the full supply chain
Record which lot number goes into which job, which customer order, and which shipment. When a finished product ships, the lot number should be on the delivery note. This completes the chain from raw material to end customer.
Use MRP software to manage it automatically
Manual lot number management works at very small scale, but quickly becomes unmanageable. MRP software like Brytebuild automates lot assignment, tracks lot movements through production, links lots to quality records, and gives you instant traceability from a single scan.
The problem with manual lot number management
Many UK manufacturers implement lot numbers — but manage them manually in spreadsheets. On the surface, this seems better than nothing. In practice, manual lot tracking creates almost as many problems as having no lot tracking at all.
- Lot numbers aren't assigned consistently — different people use different formats
- Records are updated late or not at all — the spreadsheet is always behind reality
- There's no automatic link between a lot number and quality records, job records or shipments
- Searching for which orders used a specific lot takes hours, not seconds
- Expiry date management relies on someone remembering to check, not automated alerts
- When a quality issue arises, tracing the affected lots requires manual cross-referencing across multiple spreadsheets
In a product recall, the regulators don't accept "we manage it in a spreadsheet" as evidence of adequate traceability. A recall investigation that takes your team days to complete in spreadsheets should take minutes in a properly implemented MRP system.
How Brytebuild solves lot number management
Brytebuild's MRP system incorporates lot number tracking natively across inventory, production, warehouse and quality control — connecting every stage of your process into a single, complete trace.
Seamless integration with inventory
Lot numbers are embedded into your inventory system. Every goods-in receipt is assigned a lot, and every stock movement tracks which lots are being consumed.
Barcode printing & scanning
Print lot number labels directly from Brytebuild. Scan with any phone or tablet — no specialist hardware. Scanning a lot instantly shows its full history and current location.
Quality checks linked to lots
Every quality gate — goods-in checks, in-process checks, final inspection — is automatically linked to the relevant lot number. No separate paperwork to reconcile.
Complete lot history at a glance
Scan or search any lot to see its full history: when it was received, which jobs used it, which customers received it, and all quality records. Traceability in seconds, not hours.
Expiry date management
Set expiry dates on lots at goods-in. Brytebuild alerts you before expiry and supports FIFO (first in, first out) workflows automatically — no manual checking required.
Supplier-side tracking
When goods arrive from suppliers, their lot numbers are recorded at goods-in. If a supplier's batch is defective, you can identify every item you received from that batch instantly.
With Brytebuild, a lot number recall investigation that previously took your team a day of spreadsheet searching now takes under five minutes — from scanning a product to generating a complete list of every item in that lot and every customer it was shipped to.
Best practices for lot number management
Standardise your format and document it
Write down your lot number format and make sure every person who assigns lot numbers knows and follows it. Inconsistent formats break traceability.
Assign at receipt or production start — never retrospectively
Lot numbers assigned after the fact are incomplete. Assign them the moment goods arrive or when a production run begins, every time.
Track through every stage — not just the final product
Record lot numbers at goods-in, through production, at quality gates, and on delivery notes. A chain with gaps in it isn't a chain — it's just a few disconnected pieces.
Use barcodes to eliminate transcription errors
Manual entry of lot numbers introduces transcription errors. Barcode or QR scanning eliminates this entirely — if it's scannable, it's accurate.
Include supplier lot numbers in your records
Record not just your own lot numbers but the supplier's lot number for every raw material you receive. When a supplier has a defect, you need to trace it forward — not just backwards.
Test your traceability before you need it
Run a mock recall drill — pick a lot number and see how long it takes to identify every affected item and customer. If it takes more than 30 minutes, your system needs work.
Manage expiry dates at the lot level
Set expiry dates on every lot at goods-in. Use software alerts rather than relying on someone to check. First in, first out should be automatic — not a memory exercise.
Keep records for longer than you think you need
In regulated industries, minimum retention periods are set by law. In all manufacturing, the principle is: keep lot records for at least as long as your products remain in service with customers.
Common questions about lot numbers
In regulated industries — food, pharmaceuticals, medical devices, cosmetics — lot number traceability is a legal requirement under UK and EU regulations. For other manufacturing sectors, it isn't always legally mandatory but is usually required by major customer contracts, ISO standards and increasingly by supply chain partners. Even where it isn't legally required, the operational and financial argument for lot tracking is overwhelming.
They're the same thing. "Lot number," "batch number," "lot code," and "code number" all refer to a unique identifier assigned to a group of products made or received together. The terminology varies by industry — pharmaceuticals tend to say "batch," food often says "lot" — but the concept is identical.
Technically, yes — many businesses start with spreadsheets. In practice, manual lot management breaks down quickly as volume grows. The lack of automatic linking between lots, quality records, production jobs and shipments means traceability requires manual cross-referencing that takes hours and is prone to error. MRP software like Brytebuild connects all of these automatically, making lot tracking reliable and instant rather than slow and fragile.
Lot numbers are assigned at goods-in and linked automatically to inventory, production jobs, quality checks and shipments. You can print barcode labels directly from Brytebuild and scan them with any phone or tablet — no specialist hardware needed. A single scan shows the complete lot history: when it arrived, which jobs used it, what quality checks were run, and which customers received items from that lot.
At minimum: a production or receipt date (in ISO format — YYYYMMDD — to avoid UK/US ambiguity) and a sequential batch number. For regulated products, include a product code. For multi-site operations, include a site identifier. For products with expiry, include the expiry date. The format doesn't have to be complex — it has to be unique, consistent and interpretable by your team.
Start tracking lots the right way
Brytebuild gives you full lot traceability from day one. 14-day free trial included.