What is a SKU—and how does it help ecommerce sellers?


Find out what SKU means and how they can help you with inventory management for your ecommerce business.

What is a stock keeping unit (SKU)?

A stock keeping unit—or SKU for short—is a code that helps ecommerce sellers identify products in their inventory. SKUs are usually made up of 8 to 10 letters and numbers. They make it easier to keep track of stock throughout the selling process.

To have the most accurate view of your inventory, each product you sell should have its own SKU. SKUs can be also associated with specific features like size, color, price, manufacturer, and more.


How SKUs work in ecommerce

SKUs don’t always appear on product listings, but they play an important part in the selling journey. SKUs are especially helpful for inventory management. When a customer buys one of your products, the SKU can be used to record and remove it from your inventory. By using these unique identifiers for each of your products, you can more accurately track how much you have in stock, when you need to restock certain products, and even identify popular sellers.

If you’re an Amazon seller, your SKUs can be used to connect your Amazon product listings and inventory with your own inventory records. This helps customers get the most accurate view of what’s available for purchase. And if you’re a reseller, SKUs can be an important part of your inventory management because they help you track all the different kinds of products you offer.

If you work with a third-party storage or fulfillment service provider, product SKUs can also help them understand the logistics of your business and how much space and resources are needed to support your inventory and sales.

Benefits of using SKUs

SKUs are a key part of your selling journey. They can:

  • Keep your inventory organized: SKUs make it easy to get a full view of your inventory at a glance. You can monitor what you have in stock, know when it’s time to reorder popular products, and track products across every step. Having this granular view of your inventory can cut down on errors and issues like phantom stock, so you don’t run out of products without realizing it.
  • Enhance your customer’s shopping experience: Having a clearer view of your inventory means you can provide the most current selection to customers. This can help them make purchasing decisions when an item starts to run low because it helps notify them when to stock up on their favorite products. SKUs also help you stay on top of reorders so you never run out of customer must-haves.
  • Help you plan ahead: You can use SKUs to prepare for busy seasons, sales, and marketing opportunities. For example, if you sell a product that’s about to be discontinued, you can use data related to your inventory to help you launch a flash sale and promote it across social media to help drive sales. Or if you offer a seasonal product that routinely sells out, using SKU data can help you determine how much you need to reorder to prepare for your busy season—and how soon.
  • Help in efficient shipping: While making sales is important, fulfilling is also an important part of the process. As you track each product through the selling journey, SKUs can help you see what’s ready for shipping, what’s already shipped, and what may be experiencing an issue so you can troubleshoot accordingly.
  • Support third-party service providers and fulfillment services: By sharing your inventory data with your service providers, you help ensure everyone is aware of your inventory and capable of providing the level of service customers expect.

If you sell a small number of products, you may not need to assign SKUs until you expand. But if you have an extensive inventory, assigning SKUs to your products can help set you up for selling success.

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SKU vs. product ID or GTIN

A SKUs isn’t the only code connected to a product. There are also product IDs or Global Trade Item Numbers (GTINs). A GTIN is often found above or below the barcode on a product. These numbers are different from a SKU and identify your product across separate businesses.

The most common product IDs or GTINs are:

  • Universal Product Code (UPC): A standard identifying code connected to a product.
  • International Standard Book Number (ISBN): A product identifier specifically for books, and connected to its publication date.
  • European Article Number (EAN): Also known as an international article number, this code is assigned to products in Europe.
  • Japanese Article Number (JAN): Also referred to as an international article number, this code is assigned to products in Japan.

SKUs are sometimes confused with UPCs and other GTINs, but these codes serve different purposes. A SKU is used for internal inventory management and tracking and is connected to a specific business. A UPC is a standard number that’s connected to a product no matter who is selling it. For example, let’s say you and a competitor sell the same product. You and the other seller would have different SKU numbers for that product, but it would have the same UPC.

You’ll usually need a GTIN to create new listings for products in the Amazon store, and they can also help you match your products to listings when they are already part of the Amazon catalog.

Review GTIN requirements by product category

How SKUs work when selling on Amazon

SKUs are important for managing and tracking your own inventory, but they help Amazon track products too. Amazon uses SKUs to connect your units to the product detail page in our catalog. When you enter or upload a SKU, Amazon creates a record for it.

To ensure your products are properly accounted for, it’s important that:

  • You have a separate SKU for every product in your inventory
  • Your existing SKUs remain unchanged, unless you delete the product

If you’re a direct-to-consumer—or DTC—seller, you may not have SKUs for your products. You may not need SKUs for your products until you’re ready to expand your inventory and reach.

You don’t need to create SKUs to sell your products in the Amazon store. You can add products to our catalog using an Amazon Standard Identification Number (ASIN) or GTIN, and we’ll create and assign a SKU on your behalf. You can also create your own SKUs when you list your products for sale in the Amazon store.

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Sellers are thriving on Amazon
While each seller story is unique, our goal is always the same: support seller growth and success. In 2022 alone, US-based independent sellers sold more than 4.1 billion items to customers worldwide, and averaged more than $230,000 in sales.

SKU vs. Amazon Standard Identification Number (ASIN)

If you’re planning to sell with Amazon, you should know about the Amazon Standard Identification Number (ASIN) and how it’s different from a SKU. An ASIN is a combination of 10 letters and numbers that is assigned to a product by Amazon. Each Amazon product listing has a unique ASIN. This helps Amazon keep track of all products that appear in our catalog and optimize pages for search.

Most products on Amazon have an ASIN, GTIN, and SKU, but only the SKU is used for your internal inventory.


How to create and manage SKUs for Amazon sales

To create a unique SKU for a product:

  1. Log in to your Amazon selling account.
  2. From the main menu, click Catalog, then click Add Products.
  3. Enter the product’s GTIN, ASIN, or name in the search bar, then click Search.
  4. If the product is already a part of the Amazon catalog, find and select it from the search results. Then follow the prompts and enter the SKU information in the SKU field, along with offer details in other fields.
  5. If the product isn’t in the Amazon catalog, click Create a new listing on the search results page. Then choose a product category and fill out each relevant field with information about your product, including the SKU.

To manage products by SKU:

  1. Log in to your Amazon selling account.
  2. From the main menu, click Inventory, then click Manage All Inventory.
  3. On the Manage Inventory page, you’ll see all your active product SKUs and can organize and access related product information.
Amazon product IDs: GTIN, UPC, EAN, ISBN, ASIN
Learn about Amazon product IDs, when you’ll need one and how to find or obtain one. Most products sold on Amazon are required to have an industry standard product ID.

Ready to start assigning SKUs to your products?
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Mickey Toogood
Mickey Toogood
Mickey Toogood is a Sr. Content Marketing Manager at Amazon. He’s passionate about connecting sellers with ecommerce opportunities. He also loves books, travel, and music.