E-commerce & inventory
SKU vs UPC vs Barcode: What’s the Difference?
SKU, UPC and barcode describe three different layers of a product system: an internal code you control, a standardized product identifier used across organizations, and a machine-readable symbol that carries a value.
Updated September 13, 2026
A SKU is an internal stock code created by your business. A UPC is a standardized 12-digit GTIN used to identify a trade item across retailers and supply-chain partners. A barcode is the scannable visual carrier; it can represent a UPC or, in internal workflows, a SKU or another identifier using a suitable symbology such as Code 128. One product can legitimately have both a SKU and a UPC.
SKU vs UPC vs barcode at a glance
| Term | Who controls it? | Main job | Globally standardized product identity? |
|---|---|---|---|
| SKU | Your business | Internal inventory and reporting | No |
| UPC / GTIN-12 | Assigned under GS1 identification rules | Shared retail product identification | Yes, when properly assigned |
| Barcode symbol | Generated from data using a symbology | Make a value machine-readable | Depends on the encoded identifier |
A SKU belongs to your internal inventory system
Shopify defines a SKU as an optional code that identifies a product within your business. You can create your own SKU format, and unique SKUs make inventory tracking and sales reporting easier.
Because a SKU is internal, another seller can use a completely different SKU for the same physical product. That flexibility is useful for warehouse locations, variants, purchasing and reporting, but it also means a SKU should not be presented as a globally registered product identifier.
A UPC is a standardized product identifier
UPC commonly refers to a GTIN-12. GS1 defines GTINs as global identifiers for trade items, and retailers or marketplaces can use them to match a product across organizations rather than only inside one merchant’s database.
Creating a barcode image does not create a valid UPC allocation. If a marketplace requires a GTIN, use the identifier assigned for the product under the appropriate GS1 or manufacturer process.
A barcode is the machine-readable carrier
The barcode is the pattern a scanner reads. What that scan means depends on the encoded value and the system receiving it. A UPC-A barcode normally carries a GTIN-12. An internal Code 128 barcode can carry a SKU, serial number or asset identifier instead.
This is why “I need a barcode” is incomplete. First decide what identifier the workflow needs, then choose the symbology that the scanner and receiving software expect.
Most commerce systems can use SKU and barcode fields together
Shopify keeps SKU and barcode/GTIN as separate product data concepts. The SKU supports internal operations, while a barcode value can support scanning and external product identification. Using both is normal when the business needs internal organization and shared retail identity at the same time.
- Use a SKU for your own stock and reporting logic.
- Use the assigned GTIN/UPC/EAN when a marketplace or retailer requires standardized identity.
- Use a barcode carrier that matches the scanner and data type.
- Do not copy a SKU into a GTIN field merely to satisfy a required form.
Can you put a SKU in a barcode?
Yes, when the barcode is for an internal workflow and the chosen symbology supports the SKU characters. Code 128 is a common practical option for alphanumeric internal identifiers. That creates a scannable SKU label; it does not turn the SKU into a UPC or GTIN.
Common questions
Frequently asked questions
Is a SKU the same as a UPC?
No. A SKU is an internal code created by a business. A UPC commonly refers to a globally standardized GTIN-12 used across retail and supply-chain systems.
Is a barcode the same as a UPC?
No. UPC is the product identifier concept commonly associated with GTIN-12, while the barcode is the scannable symbol. UPC-A is the retail barcode carrier commonly used for a 12-digit GTIN.
Can the same product have both a SKU and a UPC?
Yes. The SKU can identify the item inside your business while the UPC/GTIN identifies the trade item across external systems.
Can I barcode my own SKU?
Yes for an internal workflow, provided the selected symbology and scanner support the SKU characters. Code 128 is a common option. The resulting barcode does not make that SKU a registered GTIN.
Sources & standards
Technical claims in this guide are checked against primary or official documentation where available.