What Are the Different Types of Barcodes and Labels and What Is Their Purpose

Through years of self-checkout, most people can recognize a barcode but rarely do they understand the purpose of the code. Outside of a random configuration of black lines and numbers, most consumers are left in the dark after the item is rung up for purchase. Once you begin factoring in the different types of barcodes, like SKU numbers and UPCs, then you can bet even more minds will be boggled. In actuality, there are many different types of barcodes, all of which serve their unique purposes. 

If you’ve found yourself asking “what does a SKU number stand for?” or “what happens to an item after its barcode is registered?” you might be happy to learn you’re not alone. Many online eCommerce merchants can get confused by the different barcode types, but different codes often have different intended uses. By knowing what a barcode is and some of its different types, approaching them as a merchant can become quite easier. 

In this article, ShipCalm explores what a barcode is, the significance of what a SKU number is, as well as what these codes might mean for your inventory tracking. 

What is a Barcode?

To put it simply, a barcode is a rectangle with various black lines of differing thickness and heights, with white space and numbers on the bottom side. The white space and numbers register as specific products and their data. Barcodes are virtually everywhere, from store-bought grocery items to check-in desks at hotels, especially after the pandemic created more opportunities for their use. The condensed information makes collecting the item’s information instantaneous and also provides merchants and businesses with welcomed clarity about their inventory control. 

While there are various types of barcodes, they’ll fall into one of two categories. Linear codes, which include popular eCommerce formats such as UPC and EAN, and matrix codes, which are the QR codes you might be more accustomed to seeing nowadays. 

What is a SKU?

Now that you understand what a barcode is, it’s natural to ask yourself what a SKU number is as well. SKU stands for “stock keeping unit” and is an alphanumeric code created by merchants to track their inventory internally. Every business will feature its own unique guidelines for SKU creation, but every individual product will have its alphanumeric code. When making decisions based on inventory management, it’s important to have a reliable way of tracking business to secure efficiency. 

Every company will have its own system of rules for creating and managing SKUs. While each company is unique, typically a SKU is made up of 8-10 letters and numbers that represent the item’s features. This could include the product’s size, product number, color, model number, or other identifiers. Especially for eCommerce businesses that might need to replenish their inventory regularly, knowing the ebb and flow of commerce traffic is invaluable. 

What is a UPC Code?

Another frequently spotted code that you might be familiar with in the eCommerce space are UPCs, or Universal Product Codes. UPCs are universally unique codes consisting of 12 letters and numbers alongside a corresponding barcode, which is assigned to a specific product. The code will remain the same regardless of where it’s sold, which merchant is selling it, or how the transaction is made. Due to their universal regard, UPCs are regulated by an international non-profit called the GS1, which is where businesses can purchase UPCs for their products. 

When breaking down the 12-digit alphanumeric code, the first 6-9 digits will be the company prefix to help identify the intellectual property rights. The next 2-5 digits are chosen by the owner of the UPC. Regardless of how the other digits are used, the last digit will always be the sum of the previous digits, which effectively guarantees that there will never be two identical UPCs. 

What is ASIN?

Many online businesses sell their goods through Amazon, which is why the eCommerce titan has adapted to the inventory influx with their own unique UPCs. ASIN stands for Amazon Standard Identification Number and consists of 10 alphanumeric digits for products assigned by Amazon. With a catalog that includes billions of inventory, the ASIN allows Amazon merchants to track their inventory more easily. ShipCalm proudly partners with many Amazon sellers and is happy to help eCommerce businesses with their Amazon inventory fulfillment and management. 

SKU vs. UPC Codes

SKU numbers and UPCs are often confused with one another due to being in the same world of barcodes, but they’re actually very different. While a SKU number will vary widely from business to business, a UPC will always look relatively similar to another despite always being unique. There are numerous distinctions between SKU numbers vs. EPCs, which include:

Alphanumeric vs. numeric codes

One of the most obvious differences between SKU numbers and UPCs would be the codes themselves. SKU numbers are alphanumeric codes, virtually always including both letters and numbers, and can be any length as long as the merchant knows the code. On the other hand, a UPC can only include numbers and is capped at 12 digits. 


Another significant distinction of a SKU number compared to a UPC is their origin. As we explained, a UPC can only be obtained by purchasing one through GS1, an international non-profit organization. SKU numbers are created much more easily, and at a fairly low cost. Any merchant can create a SKU number for their inventory as long as they have access to the data necessary and a reliable printer. 

Internal vs. External Uses

Perhaps the most prominent difference between SKU numbers and UPCs are their intended uses. A UPC is a universal code that allows anyone from anywhere the ability to track that item if they have the data, so its use is primarily external. SKU numbers are mostly used in-house for the sake of online merchants understanding their inventory flow better. 


Another significant way SKU numbers are different from UPCs is their overall permanence. SKU numbers can change fairly frequently based on the business’ needs or changes. It’s fairly simple to remove, add, and modify a SKU catalog as long as the merchant has access to the necessary data. UPCs, on the other hand, cannot be changed. After the UPC is created and assigned, that product’s UPC is not possible to modify. 

ShipCalm Can Help With Understanding Different Barcode Types

When diving into the world of eCommerce logistics, it’s normal to get occasionally overwhelmed by the different types of barcodes and what they might mean, from UPCs to SKU numbers. At the end of the day, these unique codes are designed to help merchants track their inventory, so if you buy and sell items online it’s suggested to understand their intended uses. Luckily, a 3PL company like ShipCalm can help! 

Regardless of whether or not your business has thrived for years or is just now getting its footing, ShipCalm’s affordable services provide eCommerce businesses with the tools needed to grow. Our comprehensive inventory management software and fulfillment optimization process allow you to save time and money on tracking inventory and spend more time making your customers happy. Contact ShipCalm to learn more today! 

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