What Is a SKU and How Should You Use It?

What Is a SKU and How Should You Use It?
A SKU is a unique number assigned by a retailer to items in their inventory. Read more on SKUs and how you can get free inventory management from Square.
by Square Mar 11, 2024 — 6 min read
What Is a SKU and How Should You Use It?

What Is a SKU and How Should You Use It?

In the world of retail-related acronyms, SKU is likely one that you’ve heard a million times, but you may not know the meaning.

SKU stands for “stock keeping unit,” and, as the name suggests, it is a number (usually eight alphanumeric digits) that retailers assign to products to keep track of stock levels internally. If a product has different colors and sizes, each variation has a unique SKU number.

sku vs. UPC code

SKUs versus UPC codes

You may have heard SKU and UPC used interchangeably. They are similar but serve different purposes for in-store and online retailers.

A UPC, or universal product code, is a 12-digit numeric code that is attached to products wherever they are sold for external use. (It’s often referred to as a “UPC code,” awkwardly translating to “universal product code code.”)

So a product has the same UPC no matter where it’s sold, but different stores assign it different SKUs. SKUs are typically unique to a single retailer.

Then again, there are a lot of retailers that use UPCs as SKUs. But smaller shops (especially those that make their own products) may find it beneficial to create their own SKU system.

SKU management

If you’re going to use SKUs, their management is incredibly important. SKU management allows you to analyze the cost of carrying each product, so you can be sure that every piece of inventory meets the financial objectives of the business.

When done well, SKU management allows you to optimize your inventory levels and purchasing (and increase revenue). If done poorly, you’ll have high inventory holding costs and less available capital.

Here are the best practices to follow when creating SKUs:

You can manage SKUs manually or you can take an automated approach.

Manual SKU management

If you go the manual route, you need to calculate two metrics — SKU ratio and the sales ratio — and then compare them.

Start by looking at your product catalog and making a list of all your SKUs in a spreadsheet. For each SKU, note the price, how much it cost you, and the gross profit. (Subtract your cost from the price to determine your gross profit.)

Then create gross profit ranges in your spreadsheet (less than $20, $20–$29.99, etc.) and note how many SKUs fall in each range. Divide the number of SKUs in a range by the number of total SKUs (and multiply by 100) to get your SKU ratio for each range.

Using the same gross profit ranges, note the number of units sold (in a given period of time). Then divide the number of units sold in each gross profit range by the total units sold (and multiply by 100) to get the sales ratio for each range.

In a spreadsheet, compare the SKU ratio and sales ratio of each gross profit range. (If you’re more of a visual person, you can also plot this information on a graph to see how your SKU ratio compares to your sales ratio.)

Your best-performing products fall in the gross profit range that has a sales ratio significantly higher than the SKU ratio. It means there is high demand for those products (and potential for generating more sales if you increase inventory or marketing).

Your gross profit range where the SKU ratio is higher than your sales ratio? Those are your worst performers. It means there is too much supply, and you should reduce inventory and marketing (or even stop selling the products).

Automated SKU management

That whole process may seem a little tedious, but don’t worry; you can automate SKU management. Automating your SKU analysis reduces costs and improves the accuracy of your data.

To automate the process, you want to leverage POS systems with integrated inventory management and other tools like barcoding. Using software to manage your inventory allows you to electronically track items in real time and automatically update inventory. In addition, built-in analytics help you create more efficient purchasing processes and more effective sales and marketing strategies.

The benefits of using SKUs to manage your business

SKUs provide insight into your business’s lifeblood — your inventory. It’s no surprise then that using SKUs properly can benefit businesses immensely when it comes to inventory management, customer experience, and even supply chain management.

Here are the top ways managing your SKUs, with the right technology, can improve operations and customer satisfaction. 

Using SKUs for inventory management

SKUs are typically the easiest way to track an item’s availability across all locations, whether that be in person or online. Managing your SKUs with an intuitive point-of-sale (POS) system, like Square for Retail, gives businesses a line of sight into how products are moving across all locations. When you know how your products are selling (or not selling), you can make informed decisions on when to run a discount, when to move inventory between store locations, and when to reorder product from suppliers. Investing in a POS system that automatically syncs inventory and sales data using SKUs will help your business take quick action based on real-time insights before ever running out of stock or running an unnecessary discount. 


SKUs can even improve the customer experience.

Using SKUs to track your stock will not only improve your inventory buying, but it can also help employees better serve customers. Using an intuitive and well-organized SKU management system enables staff to look up product information quickly and accurately to answer customer questions on the spot. For example, if a customer is visiting a store in person and the size of sweater they’re interested in is not in stock at that particular location, you can have them order online or visit a nearby store where it is in stock.

Providing customers with the information they need quickly can help build brand loyalists. 

Forecasting sales and optimizing your supply chain with SKUs

Just like managing your SKUs well gives you a better shot at nailing inventory management, it can also improve your demand forecasting, or the ability to accurately predict what customers will want to buy and in what quantities throughout the year. Developing an accurate demand forecast will help avoid understocking and missing out on sales or overstocking and carrying unwanted inventory liability.   

By using SKUs to get a clear picture of your available stock and sell-through patterns by product and product category, it becomes easier to predict sales patterns. When you’re able to forecast your sales demand accurately, it enables buyers to work with suppliers with enough advanced notice to secure the products required to maximize sales — typically at a better rate.

Analyzing your SKU-level inventory and sales data using vendor sales, projected profit, and sell-through reports available with Square for Retail is easy and provides business with the information they need to negotiate favorable supplier agreements and predict sales demand with better accuracy, ultimately reducing inventory liability. 

Learn More

Master Your Supply Chain

Managing SKU numbers with Square for Retail

You can use Square for Retail to print labels for all your products that include a SKU.

If you don’t yet have one, devise an easily decipherable code for generating SKUs, referencing information like the type of item, size, color, maker, etc. If you’re not interested in creating your own system, try a SKU generator.

In your Square for Retail point of sale, start logging your products in your Square Dashboard. To enter a new product, click Create Item in the top-right corner. Next, fill in the item information (including SKU number), upload a photo, and add the variation information, like price, size, and number of items in stock.

After you’ve added everything to your Dashboard, you can organize your inventory by creating various categories, like jewelry, shoes, and clothing. Then, add products to categories by clicking Assign Item and checking the appropriate boxes. You can also use your Dashboard to delete items. If you have multiple locations, keep in mind that employees only have the ability to edit variation prices at the locations where they have access.

Once you’ve added items, go to the Inventory Management section of your Dashboard. Then click Stock > Print LabelsLearn more about printing labels in our Support Center.

Don’t need these advanced inventory features? Square Point of Sale, our free POS app, includes free inventory management software built for smaller businesses. Read more about how Square compares with Shopify and other POS systems.

The Bottom Line is brought to you by a global team of collaborators who believe that anyone should be able to participate and thrive in the economy.


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