What is an item number?
An item number, also called an article number or product number, is a unique code that identifies a product in a company’s systems. It appears on purchase orders, invoices, price lists, stock reports and warehouse labels, so everyone refers to exactly the same product.
Core principle: One product variant, one item number, used the same way in every system.
Item number vs SKU, GTIN and other codes
| Code | Who creates it | Used for |
|---|---|---|
| Item number | The company (supplier or buyer) | Orders, invoices, internal systems |
| SKU | The seller, for its own stock | Inventory and warehouse management |
| GTIN / EAN | Licensed through GS1 | Worldwide unique ID, printed as a barcode |
| MPN | The manufacturer | Identifying the original part or model |
| ASIN | Amazon | Product listings on Amazon |
In many shops, the item number and the SKU are the same code. In B2B, a buyer often has its own item number for your product, so your order confirmations and delivery notes may need to show both.
Good practice for item numbers
- Give each variant (size, colour, pack size) its own item number.
- Keep numbers short, without spaces or special characters, and never reuse them for a different product.
- Map item numbers to GTINs, so the warehouse can scan barcodes and match them to your orders.
- Send your fulfilment warehouse a product list with item numbers, GTINs, dimensions and weights before the first delivery.
Example: A supplier sells a cleaning spray to a retail chain. Its own item number is CL-500-1L, the chain lists it under its number 4471823, and the bottle carries an EAN-13 barcode. The delivery note shows all three, so the retailer’s warehouse can book the delivery in without questions.
Frequently asked questions
What is an item number?
A unique code a company uses to identify a product in its orders, invoices and stock systems.
Is an item number the same as a SKU?
Often, but not always. A SKU is the seller’s stock code; an item number can also be a supplier’s or buyer’s product code.
Is an item number the same as a barcode?
No. A barcode usually carries a GTIN, a worldwide unique number. The item number is the company’s own code.
