The Complete Guide to Stock Keeping Units (SKUs)

By Sunaina Patnaik, Content Marketing Senior Analyst

Every product you've ever bought has a secret identity. It’s a unique code that keeps the entire retail world from descending into chaos. Called a stock keeping unit (SKU), it’s an alphanumeric string assigned to every distinct product variant a business sells. Whether it's a red t-shirt in medium size or a 500ml bottle of shampoo, each gets its own SKU. Behind the scenes, these humble codes power inventory management, sales reporting, and supply chain decisions across your commerce business.

SKUs are typically eight to ten characters long, combining letters and numbers to give every product a unique, scannable identity. Unlike random barcodes, SKU codes are deliberately structured. Each character reflects a specific product attribute, such as price, size, color, or manufacturer, arranged in order of importance so the most critical information is instantly readable at a glance.

For example, a clothing retailer's SKU numbers might look something like this:

Categorization such as this gives you the tools to proactively organize your warehouses. When combined with retail inventory management software, you can build a comprehensive catalog of every item you stock. So when a customer order comes in, you know exactly what's available and where to find it.

SKUs are internal codes, created and used solely by the business that assigns them. Unlike universal product codes, they aren't standardized across retailers or industries, which means the same product can carry a completely different SKU depending on who's selling it. This flexibility is what makes SKUs so powerful! They can be tailored to reflect whatever attributes matter most to your business — whether that's supplier, size, color, or category. Let’s understand more about each product codes:

A Universal Product Code (UPC) is a 12-digit barcode number assigned by GS1, a global standards body. Every UPC is unique to a specific product and remains the same regardless of the retailer. You'll find UPC codes on most packaged consumer products, and they get scanned at the checkout counter to pull up a price.

A Global Trade Item Number (GTIN) is an umbrella term for a family of internationally recognized product identifiers, including UPCs and EANs. Assigned by GS1, GTINs are used throughout global supply chains to identify products consistently across countries, systems, and trading partners. Think of it as the universal language that lets retailers, suppliers, and logistics providers refer to the same product without confusion.

A Price Look-Up (PLU) code is a four or five-digit number used to identify loose or unpackaged items. This includes fresh produce such as fruits, vegetables, and bulk foods. Standardized by the International Federation for Produce Standards (IFPS), PLU codes help checkout staff and point-of-sale (POS) systems quickly identify and price items that can't carry a traditional barcode.

A serial number is a unique identifier assigned by a manufacturer to a specific unit of a product. Unlike SKUs or UPCs (which identify a product type), a serial number distinguishes one physical item from another of the exact same model. They're commonly used for electronics, appliances, and vehicles — anywhere that warranty tracking, repairs, or ownership records matter.

A barcode is a visual, machine-readable representation of data, typically a series of parallel lines or a square matrix (like a QR code) that encodes a numeric or alphanumeric string. Barcodes don't hold data themselves, but display an underlying code (such as a UPC, GTIN, or SKU) in a format that scanners read instantly. They're the bridge between a physical product and the digital systems that track it.

Finding a SKU depends on where you’re in the buying or selling process. For shoppers, SKUs tend to surface on packaging, price tags, and online product listings. For businesses, they're most reliably found within inventory management systems, where every product is classified and searchable. Here are the most common places to look:

• Packaging: SKU numbers are often printed directly onto product packaging, typically on a small label alongside the barcode or product details.
• Price tags: In physical retail stores, SKUs frequently appear on price tags, making it easy for staff to identify and reorder products.
• Product listings: When shopping online through platforms like Amazon, many merchants include the SKU within the product description or specifications section.
• Receipts: Some POS systems print SKU numbers on customer receipts, either as an alphanumeric code or in barcode form, depending on the retailer's setup.
• Inventory management software: For businesses using an inventory or sales management system, every product is assigned a SKU that makes searching, sorting, and reporting significantly faster.

SKUs do far more than keep a warehouse tidy. They create a common language that connects inventory, sales, and customer service under one system. If you manage large or complex product catalogs, the operational advantages compound quickly. Let’s look at its benefits:

SKUs allow you to categorize products based on their attributes, giving every item a logical home in the warehouse. This speeds up retrieval and makes stock counts more accurate. Products with similar-looking SKUs — such as variants that differ only by size or color — should always be stored in physically separate locations. Keeping them apart reduces the risk of mis-picks, where a warehouse staff pulls the wrong item, leading to incorrect orders, customer complaints, and costly returns. And remember, poor experiences and customer complaints are the number one for customers to abandon a brand.

A well-structured SKU system enables significantly faster item location. When an order comes in, staff can search the inventory by SKU, pinpoint the product's warehouse location, and pack and ship it without delay. Beyond speed, this consistency translates into a more reliable experience for the end customer. Fewer errors, faster order fulfillment, and greater trust in the brand!

Because every product variant carries a unique SKU, you can conduct faster, more accurate stock counts and feed that data directly into your inventory management system. This granular visibility means you can reorder at the right time, avoid costly stockouts, and keep an eye on inventory shrinkage — whether from damage, theft, or administrative error.

Another underrated benefit of SKUs is their ability to sharpen sales analysis. Tracking performance at the SKU level helps identify which products sell fastest, generate the highest margins, and drive the most revenue. These insights are invaluable for sales forecasting and your overall strategy.

If SKU data shows a particular t-shirt consistently sells out, you can increase stock levels, align marketing campaigns around it, and even position it at eye level in-store to capitalize on demand. The result is smarter planning and more predictable revenue growth.

SKUs serve as an internal language that keeps every team (from warehouse operatives to sales reps) aligned on the same product data. Rather than relying on product descriptions that may be confusing, employees can reference a single SKU to instantly pull up the details they need. If a sales rep needs to share product information with a customer or escalate a query internally, the SKU makes that handoff fast, accurate, and unambiguous.

SKUs enable customer service teams to check stock availability and respond to queries with confidence, reducing wait times and improving customer satisfaction. Ecommerce businesses can use SKU data to power artificial intelligence (AI) or automated recommendation engines for similar or complementary products at the point of purchase. Together, these capabilities help you deliver faster, more personalized service that keeps customers coming back. This improves customer experience and thereby boosts customer retention rates.

Every product that moves through a warehouse — whether arriving from a supplier or leaving for a customer — is governed by its SKU. They’re the operational backbone of both inbound and outbound logistics, and ensure accuracy at every physical touchpoint.

When a delivery arrives, the receiving process sets the tone for everything that follows. Warehouse staff scan each item's SKU to:

• Verify the product matches the original purchase order
• Confirm quantities against what was invoiced
• Assign each item a precise, system-designated storage location

Any scanning error at this stage — a missed item, a wrongly received variant — creates a discrepancy that cascades through stock counts, order fulfillment, and financial reporting down the line.

When a customer order is picked, SKUs act as a final accuracy check before anything leaves the warehouse. As operatives pack each box, they scan the SKU of every item, which:

• Confirms the correct product and variant are being shipped
• Verifies the quantity matches what was ordered
• Triggers an immediate system alert if there's a mismatch and stops the wrong item before it reaches the customer

Without SKU-driven accuracy at both ends, even a well-organized warehouse leads to mismatched orders, phantom stock, and returns that ruin both margins and customer trust.

There's no universal rulebook for creating SKUs. The system you build should reflect how your business thinks about its products. That said, the most effective SKU structures share a few common principles: they're logical, consistent, and easy for any team member to read and interpret at a glance.

Every SKU starts with a broad, two to three-character code representing its department, product category, or manufacturer.

You can create your own coding system here, like abbreviations to keep it simple. For instance, clothing would become CL, while accessories could be labelled AC. For suppliers, Adidas becomes ADI, Nike becomes NK, and New Balance becomes NB. How you create and label these categories is up to you. Just pick a reliable system and stay consistent.

Next, fill out the additional SKU characters with product information, such as size, color, product type, and any additional subcategories. It’s best to start with the most general classifications on the left and get more specific. For some categories, assign a number to each possible value. For instance, when assigning values to colors, you could use:

• 1 - Black
• 2 - Blue
• 3 - Red
• 4 - Green

The product attributes you choose and the way you display them are up to you. Consider what’s important for your business and create a system that’s consistent and easy to understand.

The first two steps would work perfectly if every product variant was unique, but – as you know – it’s common to stock products that are completely identical. To help with this, make the final SKU characters sequential numbers (such as 001, 002, 003). This tracks your current inventory levels and the exact chronological order of your purchases.

An inventory management system is essential to track all the SKUs you generate, especially if you’re handling a wide variety of products. Software like this provides a centralized database to categorize each SKU under one roof, giving you complete visibility over every product you own.

If you’d like to avoid the tedious task of creating SKUs yourself, commerce platforms can help create your SKUs automatically. Doing so will reduce manual errors that could lead to inventory shrinkage. It’ll also save valuable time so you aren’t wasting your days manually assigning codes to every item. Agentforce Commerce can generate SKUs based on your criteria and rules — all while tracking and updating inventory in real time so you know exactly how much of each product classification you have on hand.

Lastly, you should generate barcodes that serve as machine-readable versions of your SKUs. These barcodes can then be attached to your product labels so employees can scan them during a sale or to find more information about a product. A great inventory system can automatically generate barcodes for each SKU. When your rep scans a barcode at checkout, the system will automatically update to reflect the sale. This is a huge plus when you’re trying to make your inventory management more efficient.

A poorly designed SKU system can create more problems than it solves — from warehouse confusion to software errors that disrupt your operations. Most mistakes stem from inconsistency, over-complication, or shortcuts taken early on that become increasingly difficult to undo as the business scales. Here are the most common pitfalls to avoid:

• Reusing old SKUs: Never reassign a SKU from a discontinued product to a new one. Even if the old product is no longer sold, its SKU may still exist in historical sales data, financial records, or customer order histories. Reusing it corrupts that data and makes accurate reporting nearly impossible.
• Overly complex codes: SKUs that are too long or contain too many variables are difficult for staff to read, remember, and enter manually without errors. As a rule of thumb, keep SKUs between 8 and 12 characters — enough to be descriptive, and short enough to be practical.
• Using special characters: Symbols such as /, #, @, and & may seem harmless, but many inventory management systems, ecommerce platforms, and enterprise resource planning (ERP) tools struggle to process them. Special characters frequently break data imports, corrupt spreadsheet formulas, and cause sync failures between software integrations.
• Starting codes with a zero: Leading zeros are routinely stripped by spreadsheet software like Excel, which reads them as numbers rather than text. An SKU like 00145BKM becomes 145BKM the moment it's opened in a spreadsheet, instantly breaking your naming convention.
• No standardised format: Without a consistent structure agreed upon across teams, SKUs quickly become a patchwork of different conventions. Establish a clear format from the outset and document it so every new product and every new team member follows the same system.

Here are eight ways you can use SKUs to improve your day-to-day business operations:

1. Track your stock levels: SKUs allow you to track inventory in granular detail. This helps you predict when it’s time to order new products while avoiding phantom inventory concerns.
2. Forecast demand and sales: When you sync your SKUs with your sales solution, you’ll see which products are flying off the shelves and which aren’t, letting you predict when it's time to place an order or reduce your inventory. You can also consider product bundling based on such data.
3. Optimize resource allocation: By extrapolating SKU data, businesses get insights into demand trends. This helps optimize your staffing levels so you’re always equipped for busy periods.
4. Build your online retail store: SKUs streamline the process of building your digital storefront. This way, you’ll classify products into similar categories and improve the customer experience.
5. Develop new sales opportunities: As SKUs group products into similar categories, you and your sales team get insights into upselling or cross-selling to potential customers.
6. Product recommendations: Set up automatic systems that recommend similar products to customers, either when one product is out of stock or after a customer makes a purchase.
7. Designing displays: As an SKU system reveals your store’s most and least in-demand items, you can use this to optimize your displays. You could, for instance, put your most popular products on your front page, or at eye level in your store.
8. Providing better in-store customer service: SKUs let customer-facing teams locate products quickly, improving customer service interactions and satisfaction.

Remember to view SKUs through a financial lens. Analyzing performance at the individual SKU level helps you move beyond broad revenue figures and understand exactly which products are driving profit and which are quietly draining it. A useful framework for this is the SKU ratio vs. sales ratio calculation: divide the number of SKUs in a given category by the percentage of total sales that category generates.

Say a category represents 40% of your SKU catalog but contributes only 15% of revenue. That's a clear signal of over-assortment — too many underperforming variants consuming warehouse space, working capital, and operational attention. When 10% of SKUs drive 35% of sales, that category is punching above its weight — and almost certainly has room to grow. Tracking gross profit margin at the SKU level — factoring in the cost of goods, storage, and fulfillment costs per unit — gives you a precise view of which items are worth promoting, repricing, or discontinuing altogether. Over time, this SKU-level financial analysis contributes to a data-driven strategy.

Growth in a product catalog feels like progress. But if unchecked, it creates a problem known as SKU proliferation, in which the sheer volume of active SKUs undermines operational efficiency. Every SKU added to the catalog carries a hidden cost: it needs a warehouse location, a safety stock buffer, and ongoing management attention. Safety stock (the reserve inventory held to guard against unexpected demand spikes or supply delays) must be calculated and maintained for each individual SKU. This means a bloated catalog can tie up significant working capital in slow-moving or rarely ordered stock.

The knock-on effect is a warehouse pulled in too many directions at once — higher holding costs, messier replenishment cycles, and shelves quietly filling up with stock that hasn't moved in months. Left unchecked, slow-moving SKUs tie up cash that could be put to better use elsewhere. So, regularly review SKU performance as it's one of the smartest financial decisions a business can make.

All set to get started? These tips can help you create solid SKUs:

This seems obvious, but when implementing SKUs, your staff needs to understand what they’re working with. Train your teams on your format and each individual identifier. Employees should know what each abbreviation and number means in context. Create a knowledge base for them to refer to as needed.

Color is an easy way to distinguish between physical products, but if you’re exclusively selling items that come in black, it’s a redundant product category. Choose classifications that’ll actively help you distinguish between products. This will make it easier for your team to find individual items and understand customer demand better.

SKU codes have a lot more mileage than simple tracking devices. Use them to make agile, smart business decisions that support your growth. For example, you can (and should) use your SKUs to monitor sales trends over time. This provides a trove of data to optimize your staffing, prepare your inventory, budget, and even decide which products are worth marketing.

If there’s an opportunity to shorten your SKUs without losing clarity, take it. The easier you can make your codes to read, the faster it’ll be for staff to find the information they’re looking for.

You can also add dashes in between each unique identifier if you choose. This lets employees scan the codes at a glance to find the information they’re looking for. Be sure not to include any special characters, as these can be misread by software.

The number one piece of advice when you’re incorporating an SKU system into your operation? Don’t do all of the busy-work by hand.

An inventory management system will automatically generate SKUs for each of your unique products and then categorise this data in a single centralised database, creating a single source of truth that you can use to view all of your products in one place.

It’ll also help you view inventory levels in real-time based on your SKUs and schedule automatic reorder points so you never miss the chance to capitalize on demand. It’s a must for efficiency and better business decisions.

SKUs are deceptively simple! Just a short string of letters and numbers that, when designed and managed well, quietly hold an entire business operation together. From the moment stock arrives at a warehouse dock to the second an order lands on a customer's doorstep, SKUs are working in the background to keep products findable, orders accurate, and data meaningful. But a great SKU system is only as powerful as the platform supporting it.

That's where Agentforce Commerce comes in. With built-in inventory management, real-time stock visibility, and seamless integrations across your sales channels, it gives businesses the infrastructure to manage SKUs at scale — without the operational headaches. Whether you're running a lean catalog or thousands of product variants, the right tools turn your SKU data into a competitive advantage. Find out how.