SKU Management: How to Create, Organize and Control SKUs at Scale
How to build a SKU system that stays clean as your catalog, warehouses and sales channels grow.
Quick answer
A SKU (stock keeping unit) is an internal code a business assigns to each distinct product it stocks, so the item can be counted, ordered, sold and reported on. Good SKU management means three things: a consistent numbering system, a clean way to handle variants like size and color, and regular reviews that retire items that no longer earn their shelf space. Once a company has many SKUs across several locations or sales channels, inventory software such as Kechie ERP keeps every SKU accurate in real time.
SKUs look like a small detail until they go wrong. Two people create the same item under different codes. A retired code gets reused for a new product, and two years of sales history merge into nonsense. A t-shirt in five colors and six sizes becomes 30 unrelated items that nobody can report on together. Each problem is small on its own, but together they make every count, reorder and report harder.
This guide covers how to design SKUs that hold up as you grow, with real examples, the most common mistakes, and how to keep SKU counts under control.
What is a SKU?
A SKU is an alphanumeric code that identifies one specific product a business stocks, down to the attributes that matter for inventory. A "black running shoe, men's size 10" and a "black running shoe, men's size 11" need separate SKUs, because you count, reorder and sell them separately.
Your company creates its own SKUs and structures them however you need. They are meant to be read by your own team and systems, which is why a well-built SKU tells an employee something useful at a glance.
SKU vs. UPC vs. lot number vs. serial number
Four kinds of codes get confused constantly. Each answers a different question:
| Code | Who assigns it | What it identifies | Main use |
|---|---|---|---|
| SKU | Your business | A product type you stock | Inventory counts, reordering, reporting |
| UPC / GTIN | GS1 standards, licensed to the brand owner | The same product type, universally | Retail scanning, marketplaces, EDI |
| Lot number | Your business or supplier | A batch made or received together | Recalls, expiration, traceability |
| Serial number | Manufacturer or your business | One individual unit | Warranty, service, returns |
One product usually carries several of these at once. A case of protein bars might have one SKU, one UPC, and a lot number for each production run. Learn more in our guides to lot tracking and serial number tracking.
How to create a SKU numbering system
- Start with the broadest attribute. Lead with what buyers and warehouse staff group by most, usually category, brand or product line.
- Add the attributes that make each item different. Style, material, size, color, flavor or pack size, in a fixed order.
- Keep it short. Aim for 8 to 12 characters. Long SKUs get mistyped and get cut off on labels and reports.
- Use letters and numbers only. Avoid spaces and special characters that break in spreadsheets, barcodes and marketplace feeds. A single consistent separator, like a hyphen, is fine.
- Avoid look-alike characters. Leave out O (confused with 0) and I or L (confused with 1).
- Don't start with zero. Spreadsheets drop leading zeros, and 00451 quietly becomes 451.
- Never reuse a SKU. A retired code stays retired, so its sales history stays accurate.
- Write the rules down. One page that shows the code structure and abbreviation list, so every new item is built the same way.
SKU examples by industry
| Industry | Example SKU | How to read it |
|---|---|---|
| Apparel | TS-CRW-BLK-M | T-shirt, crew neck, black, medium |
| Food and beverage | BAR-PB-12CT | Protein bar, peanut butter, 12-count box |
| Health and beauty | SER-VITC-30ML | Serum, vitamin C, 30 ml |
| Industrial distribution | VLV-BRS-075-NPT | Valve, brass, 3/4 inch, NPT thread |
| Manufacturing (finished good) | CHR-OAK-NAT-FG | Chair, oak, natural finish, finished good |
| Manufacturing (component) | CHR-LEG-OAK-RM | Chair leg, oak, raw material |
Pro tip: Give a finished good and its components the same prefix, like the two chair SKUs above, so they sort together. That makes your bill of materials easier to read and audit.
How to handle size, color and other variants
Variants are where SKU counts explode. A single style in 6 sizes and 5 colors is 30 SKUs. Add a second fabric and it's 60. There are two ways to manage this:
1Flat SKUs
Every combination is its own item
This is simple to set up, but reporting on the style as a whole means adding up dozens of unrelated lines by hand.
2Style and variation
How Kechie ERP manages variants
One base item for the style, with attributes such as size, color and gender tracked as variations underneath it. You can report on the whole style or on any single variation.
In Kechie, a "t-shirt" is one item, and male, red, large is a variation of it. Buyers can see which style is selling, while the warehouse still picks the exact size and color. This is especially valuable for apparel companies, where variants multiply fastest.
SKU proliferation: how to keep SKU counts under control
SKU proliferation happens when items multiply faster than sales justify. Each extra SKU needs shelf space, safety stock, counting time and purchasing attention, and slow movers tie up cash that could fund the items that sell.
A simple twice-yearly review keeps it in check:
- Rank items by contribution. Use an ABC analysis: A items drive most revenue or margin, C items drive little.
- Flag slow movers. Look at items with low turns, long days on hand or no sales in a set period.
- Check dependencies. Before cutting an item, confirm it isn't a component in a bill of materials or a must-have for a key customer.
- Retire, don't delete. Mark discontinued SKUs inactive so their history stays in your reports.
- Set rules for new SKUs. Require a sales forecast or customer commitment before a new item or variant is created.
Kechie's pre-configured reports show turns, slow-moving stock and margin by item, so the review takes hours rather than days of spreadsheet work.
SKU metrics worth tracking
| Metric | What it tells you |
|---|---|
| Inventory turns by SKU | How often each item sells through in a period |
| Days on hand | How long current stock will last at today's sales rate |
| Stockout rate | How often an item was unavailable when ordered |
| Gross margin by SKU | Which items actually make money after cost |
| Inventory accuracy | How closely system counts match physical counts (see cycle counting) |
| Active SKU count | Whether your catalog is growing faster than revenue |
What to look for in SKU management software
Spreadsheets work for a few hundred items in one location. Beyond that, you need software that does the following:
- Real-time stock by location. Every receipt, sale and transfer updates counts immediately across warehouses.
- Variant support. Size, color and other attributes are managed under one base item.
- Channel sync. SKUs and stock levels stay aligned with Shopify, Amazon, eBay and Etsy so you don't oversell.
- Reorder planning. Reorder points, safety stock and min/max levels for each SKU. Kechie adds AI-driven min/max recommendations based on each item's actual demand.
- Lot and serial tracking. Available where your products need it.
- Barcode and UPC support. Maps your SKUs to the codes retailers and marketplaces use.
- Pre-configured reports. Turns, aging, slow movers and margin, without building them yourself.
Kechie ERP, from My Office Apps (MOA), includes inventory and warehouse management in its core package, with real-time stock across locations, style-and-variation items, and AI-driven reorder recommendations. Kechie was named to the Forbes Advisor Top 10 ERP list for 2025. Explore Kechie Inventory Management.
Frequently asked questions
What is a SKU number?
A SKU (stock keeping unit) number is an internal code a business creates to identify each distinct product it stocks, including attributes such as size or color. It's used to count, reorder, sell and report on inventory.
What is the difference between a SKU and a UPC?
A SKU is created by your business and is unique to your company. A UPC is a universal barcode number based on GS1 standards that identifies the same product across every retailer. One product often has both.
How long should a SKU be?
Most businesses keep SKUs between 8 and 12 characters, using letters, numbers and at most one consistent separator. Shorter codes are easier to read, type and print on labels.
Should every size and color have its own SKU?
Each sellable combination needs to be tracked, but it doesn't have to be a separate unrelated item. Kechie ERP manages size, color and other attributes as variations under one base style, so you can report on the style and on each variation.
What is the best software for SKU management?
Look for real-time multi-location inventory, variant support, sales channel sync, reorder planning and pre-configured reports. Kechie ERP offers all of these in one system that is pre-configured and live in weeks.
How often should you review your SKUs?
At least twice a year. Rank items by revenue or margin, flag slow movers, check whether they are used in other products, and retire items that no longer earn their place.
Get every SKU under control
See how Kechie keeps thousands of SKUs and variants accurate across every warehouse and sales channel. Click the button below to schedule your free demo.
Schedule your Kechie demo now!