A GLN (Global Location Number) is a 13-digit GS1 identifier that uniquely identifies a legal entity, a functional unit within that entity, or a physical location. GLNs appear in EDI transactions, BMEcat catalogs, and master data exchanges to identify buyers, suppliers, warehouses, and ship-to addresses.
What a GLN identifies
A GLN answers the question: "Who or where?" It identifies three types of things:
-
Legal entities. A company, a subsidiary, a department. Schneider Electric's German subsidiary has a GLN. So does Rexel's central purchasing office.
-
Functional entities. A department within a company that needs its own identifier for transaction routing. The accounts payable department at a distributor's headquarters might have a different GLN than the purchasing department, even though they share the same physical address.
-
Physical locations. A warehouse, a retail branch, a delivery dock. A distributor with 30 branches typically has 30 location GLNs plus at least one legal entity GLN.
This flexibility is what makes GLNs powerful and, at the same time, confusing. The same 13-digit format identifies companies, departments, and buildings. Context determines which type you are dealing with.
The format
A GLN is exactly 13 digits:
GLN: 4012345000009
||| |
||| +-- Check digit (1 digit)
||+----------- Location reference (variable length)
|+------------ GS1 Company Prefix (variable length, 7-11 digits)
+------------- GS1 country prefix
The first digits are the GS1 prefix, which indicates the country where the number was issued (not necessarily where the location is). The last digit is a check digit calculated using the same modulo-10 algorithm used for GTINs.
The total is always 13 digits. No more, no less. Leading zeros are significant. A GLN stored as an integer instead of a string will lose its leading zeros and become invalid.
The check digit
The GLN check digit uses the identical GS1 modulo-10 algorithm as GTINs:
- Starting from the rightmost digit (excluding the check digit), assign alternating weights of 3 and 1 moving left.
- Multiply each digit by its weight.
- Sum all the products.
- The check digit is (10 minus (sum mod 10)) mod 10.
For the GLN 4012345000009:
- Digits: 4, 0, 1, 2, 3, 4, 5, 0, 0, 0, 0, 0, [9]
- Weighted sum: 4x1 + 0x3 + 1x1 + 2x3 + 3x1 + 4x3 + 5x1 + 0x3 + 0x1 + 0x3 + 0x1 + 0x3 = 31
- Check digit: (10 - (31 mod 10)) mod 10 = (10 - 1) mod 10 = 9
You can verify any GLN instantly using the free GLN validator. It checks the length, format, and modulo-10 check digit.
Where GLNs appear in product data
BMEcat catalogs
In BMEcat 2005, GLNs identify the buyer and supplier in the header. The BUYER_GLN and SUPPLIER_GLN fields are 13-digit GLN values. When you import a BMEcat file, these GLNs tell you who issued the catalog and who it was issued to.
<BUYER>
<BUYER_ID type="gln">4398765000014</BUYER_ID>
</BUYER>
<SUPPLIER>
<SUPPLIER_ID type="gln">4012345000009</SUPPLIER_ID>
</SUPPLIER>
EDIFACT messages
In EDI, GLNs appear in NAD (Name and Address) segments to identify parties. An ORDERS message includes the buyer's GLN, the supplier's GLN, and often a ship-to GLN for the delivery location.
NAD+BY+4398765000014::9'
NAD+SU+4012345000009::9'
NAD+DP+4398765000021::9'
The qualifier 9 indicates the identifier is a GS1 GLN.
Master data management
In GS1's Global Data Synchronisation Network (GDSN), GLNs identify the data source (manufacturer) and data recipient (distributor). Every product record in GDSN is linked to the GLN of the organization that published it.
Company databases and directories
Industry directories like IEC's Common Data Dictionary and ETIM's participant registry use GLNs to identify member companies. When you look up a manufacturer in these systems, the GLN is the primary key.
Why electrical distributors need GLNs
If you exchange data electronically with any trading partner in Europe, you need GLNs. The European electrical wholesale industry has standardized on GS1 identifiers for EDI. Organizations like ETIM International and national associations (VEG in the Netherlands, FGME in France, FEH in Norway) require GLNs for electronic catalog exchange.
Even if you do not do EDI today, your GLN is embedded in every BMEcat catalog you receive from suppliers. When you set up a new supplier integration, the first thing they ask for is your GLN.
Getting a GLN
GLNs are assigned by your national GS1 organization. In the US, that is GS1 US. In Germany, GS1 Germany. In the UK, GS1 UK. You need a GS1 company prefix, which also lets you assign GTINs to your own-brand products if you sell any.
The cost varies by country but is typically a few hundred euros per year for the prefix, which includes the ability to create GLNs for your locations.
Common GLN problems in product data
Wrong length. A GLN must be exactly 13 digits. Values with 10, 11, or 12 digits are not GLNs, even if they look like they should be.
Failed check digit. Manual entry errors produce GLNs that look right but fail the modulo-10 check. Always validate the check digit before storing.
Stale GLNs. Companies merge, close locations, and restructure. A GLN assigned to a warehouse that closed five years ago is still technically valid, but routing an EDI message to it will fail.
GLNs stored as integers. Like GTINs, GLNs must be stored as strings. A GLN starting with 0 will lose its leading zero if stored as a number.
Before storing or transmitting a GLN, verify it with the free GLN validator to confirm the format and check digit are correct.
GLN vs other identifiers
GLNs are sometimes confused with DUNS numbers (Dun & Bradstreet), VAT numbers, or internal customer/supplier codes. The key difference: GLNs are globally unique, standardized, and designed for automated data exchange. A DUNS number identifies a business entity but uses a different format (9 digits, no check digit). VAT numbers are country-specific and formatted differently in each jurisdiction.
In practice, your systems will store all of these. The GLN is the one that matters for GS1-based data exchange and EDI routing.