What Is a UPC Code? A Clear Guide for Retail and Ecommerce

 A UPC code, short for Universal Product Code, is that familiar black-and-white barcode you see on almost every product in a store. It’s what makes checkout lines move faster and helps businesses keep track of what’s selling. Whether you’re buying cereal or shipping phone cases, there’s a UPC involved.

If you sell products online or in stores, you’ll likely need UPC codes at some point. They’re required by most major retailers and marketplaces like Amazon.

What Is a UPC Code?

A UPC code (Universal Product Code) is a 12-digit number paired with a barcode that helps stores and systems identify products. You’ll find it printed on product packaging, and it’s what cashiers or barcode scanners use to pull up prices and product details instantly.

Each UPC is tied to a specific product type—like a pair of black sneakers, size 10—not to each individual item. So if you sell that same sneaker in different sizes or colors, each version needs its own UPC.

UPC codes are part of a global system managed by GS1, a standards organization that keeps every code unique. Whether your product ends up on a shelf in a big box store or in a customer’s Amazon cart, the UPC makes sure it’s recognized and tracked correctly.

What Does a UPC Code Do?

A UPC code makes it easy to identify, sell, and manage products. Retailers scan it at checkout to pull up the price. Warehouses use it to track inventory. Online marketplaces rely on it to match products to listings.

Here’s what a UPC helps with:

• Faster checkout – Cashiers or self-checkout machines scan the barcode to get the price instantly.
  
• Inventory tracking – Stores and warehouses use UPCs to monitor stock levels and restock when needed.
  
• Fewer shipping mistakes – Scanning the right barcode helps pack and ship the correct item every time.
  
• Marketplace listings – Platforms like Amazon require UPCs to list your products and group them correctly.
  

In short, a UPC code keeps everything organized—from the moment you stock a product to the second it reaches your customer.

 When Do You Need a UPC Code?

You don’t always need a UPC code—but depending on how and where you sell, it might be required.

You don’t need UPCs if:

• You ship products directly from home.
  
• You run a small shop and use your own labeling system.
  
• You sell only through your own website with no third-party platforms.
  

You do need UPCs if:

• You sell in retail stores—employees need to scan your products at checkout.
  
• You list on marketplaces like Amazon, Walmart, or eBay—these platforms require UPCs to create listings.
  
• You work with wholesalers or third-party logistics partners—they use UPCs to track and manage inventory.
  

Even if you don’t need them now, it’s worth thinking ahead. If you plan to scale or start selling through new channels, UPCs are often part of the deal.

Parts of a UPC Code

A UPC code is more than just a barcode—it’s made up of 12 digits that each serve a purpose. Together, these numbers help identify the brand, the product, and confirm the code is valid.

Here’s the breakdown:

Company Prefix

The first 6 digits identify the brand or manufacturer. This number is assigned by GS1 and is unique to your business.

Item Number

The next 5 digits represent the specific product. Different sizes, colors, or versions of the same product each get a different item number.

Check Digit

The last digit is the check digit. It’s automatically calculated using a formula based on the first 11 digits. If the check digit doesn’t match, the code won’t scan properly.

Together, these numbers create a standardized code that works in stores, warehouses, and ecommerce inventory platforms.

 UPC vs. Other Codes

A UPC code is just one type of product identifier. Depending on what you sell and where, you might see or use other codes too. Here’s how they compare:

SKU

A Stock Keeping Unit is created by you—for your internal tracking only. It helps sort products by size, color, or style in your inventory system. SKUs don’t follow a global standard and aren’t scanned by retailers.

EAN

An European Article Number is similar to a UPC but has 13 digits. It’s used mostly outside the U.S. Most barcode scanners today can read both UPC and EAN codes.

ASIN

An Amazon Standard Identification Number is unique to Amazon. Every product listed on Amazon gets one. If you sell on Amazon, your product will need a UPC first, and then Amazon assigns the ASIN.

UPC-E

A compressed version of the standard 12-digit UPC, made to fit on small packaging like makeup or snack-size items. It’s still readable by scanners.

ISBN

The International Standard Book Number is used only for books. It includes details like the publisher and edition. You’ll see it on the back cover near the barcode.

Each code has its place, but UPCs are the most common for physical products sold in stores and online.

How to Get a UPC Code

You can’t make up your own UPC codes. To keep them valid and unique, you need to get them from GS1, the official global standards organization.

Here’s how to do it:

Count how many codes you need

You’ll need a separate UPC for every product variant—each size, color, or style gets its own code.

Go to the GS1 website

Head to GS1 US and choose one of two options:

• Buy a single GTIN – Great if you’re only selling a few products.
  
• Get a company prefix – Best if you have lots of products or plan to grow. This lets you create multiple UPCs under one business ID.
  

Create and manage your barcodes

Once you sign up, you’ll get access to GS1 tools to generate your codes. You can download them and add them to your packaging or labels.

Buying from GS1 makes sure your UPCs are accepted by major retailers, online marketplaces, and logistics partners.

 Best Practices

Using UPC codes the right way helps avoid scanning issues, inventory errors, and listing problems. Here are some tips to keep things running smoothly:

Buy from GS1

Always get your UPCs from GS1. Codes from unofficial sellers might not work on Amazon or in retail stores.

Don’t reuse old codes

Each UPC should match one product variant. Reusing a code for something else can confuse systems and mess up inventory.

 Keep your records updated

Track which UPCs go with which products. This keeps your listings, packaging, and inventory in sync.

Plan ahead

If you’re launching multiple products or variants, consider getting a company prefix. It saves time and keeps your codes organized under one business identity.

 Add codes to your packaging

Print the UPC barcode clearly on each product. Make sure it’s easy to scan—avoid placing it on curved or shiny surfaces.

 Conclusion

A UPC code helps your products move smoothly through checkout, inventory, and online listings. It’s a small label with a big job—connecting your product to the systems that sell and ship it.

If you’re just starting out, you might not need UPCs right away. But if you plan to grow, sell in stores, or list on marketplaces like Amazon, they’re a must.

Getting set up is simple: count your products, register with GS1, and start assigning UPCs the right way. With the right codes in place, you’re ready to scale confidently and stay organized.