A shipping message says goods were sent "from the factory" to "the warehouse". Which factory? Which warehouse, and which of its three buildings? When companies exchange thousands of orders and shipments a day, they need an unambiguous way to say who and where. In GS1 standards, that is the job of the GLN.
What a GLN identifies
The GLN, or Global Location Number, is a GS1 identifier for parties and locations. GS1 defines four kinds of thing it can identify:
| Kind | What it means | Maison Ardent example |
|---|---|---|
| Legal entity | A company or organisation that can enter into agreements | Maison Ardent, the company |
| Function | A department or role within a company | Maison Ardent accounts payable |
| Physical location | A real place, such as a site or building | The filling factory; the export warehouse |
| Digital location | An electronic address, such as a system that receives messages | The system that receives retailers' purchase orders |
Maison Ardent is a fictional perfume house used throughout this Learning Centre. Its trading partners may need several of its GLNs: one to invoice the legal entity, one to send payment queries to accounts, and one for each site that ships or receives goods.
The simplest way to place the GLN among GS1 identifiers is by the question each answers:
- GTIN: what product is this?
- GTIN plus serial: which unit?
- SSCC: which carton or pallet in transit? See what is an SSCC?
- GLN: who is involved, and where did it happen?
The full family is laid out in GTIN, batch, serial, SSCC and GLN explained.
The structure
A GLN is always exactly 13 digits. Like a GTIN, it starts with the company's GS1 Company Prefix, followed by a location reference the company chooses, and ends with a check digit calculated by the standard GS1 method. For example, Maison Ardent's filling factory might be:
9501101000018
The prefix (here 9501101) shows which company assigned the GLN. The location reference (00001) is Maison Ardent's own numbering. The check digit (8) catches reading and keying errors.
GLNs should be stable. A location keeps its GLN while it remains the same location, and GS1 has rules restricting reuse of a GLN for something else after it is retired, so old records never point to the wrong place.
How a GLN appears in a barcode
Most GLNs live in business data rather than on labels, but a physical location can be carried in a barcode using Application Identifier (414):
(414) 9501101000018
That is useful for labelling a site, a building entrance or a storage area so staff can scan "I am here" during a stock movement. For a point within a location, such as dock door 4 of the warehouse, GS1 provides the GLN extension component, carried in AI (254) alongside the GLN:
(414) 9501101000049 (254) DOCK4
The GLN identifies the warehouse; the extension identifies the spot inside it. This avoids creating a full GLN for every door and rack.
GLNs can also be written as a GS1 Digital Link, using /414/ as the path, which lets a location label be opened on a phone.
Where GLNs are used
Orders, invoices and shipping messages
When trading partners exchange documents electronically, often called EDI (electronic data interchange), GLNs are a common way to identify the buyer, the seller, the invoice recipient, the ship-from site and the deliver-to site. A retailer with hundreds of stores can say "deliver to this GLN" and the supplier's system knows exactly which store, without relying on addresses typed slightly differently every time.
Shipping and receiving
When a pallet leaves Maison Ardent's export warehouse for a distributor, the shipment record carries the pallet's SSCC, the warehouse's GLN as origin and the distributor's GLN as destination. When the distributor scans the pallet in, its own GLN records where receipt happened. The receiving side is described in why warehouses scan cartons and pallets.
Traceability events
EPCIS, GS1's standard for sharing supply-chain event data, describes each event by what, when, where, why and how. The "where" is the read point and business location, and GLNs are a common way to identify them. That gives a recall team a clear answer to "where was this case packed, and where did it go next?" The event standard is explained in what is EPCIS?, and the packing records it builds on in how individual products become cartons and pallets.
Master data and registries
Companies share GLNs with partners as part of supplier and customer set-up. The Verified by GS1 service can confirm that a GLN was issued by GS1, which company it is licensed to, and core data about the location provided by its owner.
Getting started with GLNs
For most manufacturers, a sensible first set is:
- one GLN for the company as a legal entity;
- one for each factory and warehouse that ships or receives goods;
- GLNs for any function partners send documents to, such as accounts payable, if they ask for it.
Assign them from your GS1 Company Prefix, record what each one means in your master data, and share them with partners who need them. Add more only when a partner or a traceability requirement needs a finer distinction.