A SKU (stock keeping unit) is your own internal code for a product, which you make up yourself. Build it from blocks going from general to specific — category, model, color, size — for example, TSH-105-BLK-M. Use Latin letters and digits only, capitals, one separator such as a hyphen, no spaces, and do not change a SKU once the product is on sale. A UPC or EAN barcode, unlike a SKU, is not made up: its number comes from GS1.
The usual mistake is not the naming itself but forgetting how long a SKU lives: it ends up in supplier price lists, marketplace and shopping feeds, packing slips and orders. A changed or ambiguous code then mixes up stock on every channel. Below are the SKU scheme, ready-made templates for several niches, how to code sizes and colors, and how a SKU differs from a UPC, an EAN and a supplier code.
When people ask how to create SKUs
It usually happens when the catalog grows to a few hundred items or a marketplace asks for a SKU in every listing. The seller searches for "what is a sku" and "how to create sku numbers", then asks "sku vs upc", "where do I find my sku number", "what does a sku look like" and "can I use the supplier's sku".
The last question is a trap. The supplier's code works while you have one supplier. When the same product comes from a second one, you have two codes for one item. Your own SKU does not depend on who you buy from.
What is a SKU
A SKU is a unique code a store uses to tell one product from another in its catalog, warehouse and orders. In ecommerce, a SKU, a product code and an item number usually mean the same thing: a separate code for every variant you count separately in stock.
Next to your SKU, a product record holds three more codes: the manufacturer part number (MPN — the model code on the package or in the brand's catalog), the supplier's code (the line number in their price list) and the barcode number, a UPC or EAN. They help with search and matching, but none of them replaces your SKU — the table below shows how they differ.
SKU format: four blocks from general to specific
A SKU is built from short blocks, each with its own list of codes. The order runs from the broadest to the narrowest, so SKUs of the same category and model sit next to each other in any sort.
| Block | What it means | How to build the code list | Example |
|---|---|---|---|
| 1. Category | Product type | 2–4 letters per category, fixed once | TSH — T-shirts, HOD — hoodies |
| 2. Model | A specific model within the category | A sequence number with a fixed number of digits | 105 |
| 3. Color | Color variant | 3 letters per color | BLK — black, WHT — white |
| 4. Size | Size or volume variant | As on the label or in the size chart | S, M, XL, 42 |
You can use fewer blocks: products without sizes and colors need only two — category and model. More than four blocks is rarely needed: a 20-character code is hard to read out over the phone and easy to mistype.
SKU examples for different stores
The scheme is the same, but each niche has its own blocks. The examples below are ready templates — take one and plug in your own code lists:
| Niche | Scheme | Example |
|---|---|---|
| Clothing | category-model-color-size | TSH-105-BLK-M |
| Shoes | category-model-color-size | SNK-022-WHT-41 |
| Cosmetics | brand-line-volume | LUM-SRM-050 |
| Auto parts | group-model number-position | BRK-1204-FR |
| Home and decor | category-model-material | CND-310-SOY |
| Electronics and accessories | category-model-color | CBL-007-BLK |
If your range changes all the time and products have no variants, a sequential SKU is simpler: category plus a number (CND-000318). It does not say what the product is, but you never have to invent a code for a new block.
SKUs for sizes and colors
Every variant you count separately in stock gets its own SKU: the model code stays the same, only the variant suffix changes. So T-shirt 105 in three variants is three SKUs, not one.
The shared part TSH-105 groups the variants into one product page on your site and on a marketplace, and the full code shows exactly which variant was ordered. Give all variants one SKU, and selling a black M takes stock off a white S.
SKU vs UPC, EAN and supplier code: the difference
You create the SKU, the UPC or EAN comes from GS1, and the supplier code comes from the supplier's price list. That is why one box can carry all three, and each serves its own purpose.
| Who assigns it | Can you make it up | What it is for | |
|---|---|---|---|
| SKU | You | Yes | Your catalog, warehouse, orders, feeds |
| UPC (12 digits) or EAN (13 digits) — both are GTINs | The brand owner, with a number from GS1 | No, except in-house codes with prefixes 200–299 | Scanning at checkout and in the warehouse, retail chains, marketplaces, shopping feeds |
| Manufacturer part number (MPN) | The manufacturer | No | Finding the product and matching it to the brand's catalog |
| Supplier code | The supplier | No | Ordering from the supplier, checking their price list |
UPC is the 12-digit version used mainly in North America, EAN the 13-digit version used in Europe; Google Merchant Center accepts both as a GTIN. To get your own numbers, a company licenses a GS1 Company Prefix from its national GS1 organization (GS1 US, GS1 UK, GS1 Germany and so on). The first digits show which GS1 organization issued the prefix, not where the product was made. GS1 reserves prefixes 200–299 for restricted circulation numbers — codes for in-house use, not for products sold through other retailers. A series of such codes with a correct check digit comes from the EAN-13 barcode generator.
In a Google Shopping feed the codes go into separate fields: your SKU into id (Google recommends using the SKU there), the barcode into gtin and the manufacturer part number into mpn.
SKU naming rules that keep codes working
These rules exist because of mistakes that take a long time to clean out of a catalog:
- No letters that look like digits. O and 0, I and 1 get mixed up on labels and on the phone. Either leave O and I out of letter blocks or agree that number blocks contain only digits.
- No spaces and only one separator. "TSH 105" and "TSH-105" are different strings for search. Pick one separator, usually a hyphen.
- Plain Latin letters and digits only. É looks almost like E, and a Cyrillic or Greek letter can look exactly like T, but to software they are different characters: a search for the SKU will not find the product, and a feed may reject the code.
- Fixed length for number blocks. 007 instead of 7: then TSH-007 sorts before TSH-105 everywhere.
- Do not change a SKU. It is already in feeds, orders and packing slips. A new code for an old product is a new product to a marketplace; Google Merchant Center warns that changing a product's ID overwrites the product and its history. Do not reuse a retired SKU for another product either.
- Do not put the price, supplier or season into the SKU. They change, and the SKU does not. The product record has separate fields for them.
How to create SKU numbers for a whole catalog in Excel
Code lists first, formula second: that way a thousand SKUs are built in minutes, without typing them by hand.
- Make the code lists: categories, colors, sizes. Each one is a separate sheet with two columns: name and code.
- In the product table, give each block its own column: category, model number, color, size. Store the model number as text with leading zeros (007, 105).
- Build the SKU with a formula: =A2&"-"&B2&"-"&C2&"-"&D2. The & operator works in Excel and Google Sheets in any interface language.
- Check that every SKU is unique: sort by SKU and look for duplicates (conditional formatting → duplicate values).
- Load the SKUs into your catalog together with the products. How to import thousands of items at once is in bulk product import.
When you have several suppliers and sales channels
Your own SKU pays off when the same product comes from several suppliers and sells on your website and on marketplaces: the catalog runs on your code, and supplier codes and barcodes only help find the match.
In Elbuz the product record has separate fields for this: SKU, manufacturer part number, supplier code and barcode. A supplier's price list is matched to the catalog by barcode, SKU or name, so price and stock updates change existing products instead of creating duplicates. For products without a barcode, a formula with the EAN-13 generator assigns codes with a correct check digit. How such a catalog works is on the PIM software for ecommerce page.
Who it is not for: if you have a few dozen products from one supplier, a spreadsheet with code lists and the formula from the section above is enough.
Frequently asked questions
What is a SKU?
A SKU, or stock keeping unit, is a unique product code that a store assigns itself to tell products apart in its catalog, warehouse and orders. Every variant with its own stock count gets its own SKU.
How do I create SKUs for my products?
Build each one from blocks going from general to specific: category, model, color, size, for example TSH-105-BLK-M. Use capitals, Latin letters and digits, one separator and no spaces.
What does a SKU number look like?
For clothing, TSH-105-BLK-M (T-shirt, model 105, black, size M); for cosmetics, LUM-SRM-050 (brand, line, volume). More templates are in the table by niche.
What is the difference between a SKU and a UPC?
You create a SKU yourself for your own catalog, and it can contain letters. A UPC is a 12-digit number based on a GS1 Company Prefix that identifies the product for every retailer; you cannot make it up.
Can I create my own SKU number?
Yes, a SKU is always your own code: there is no registry and no fee. Only barcode numbers such as UPC and EAN have to come from GS1.
Where do I find my SKU number?
Your own SKU is in your catalog or store admin, because you assign it. The manufacturer part number is on the package or in the brand's catalog, the supplier code in the supplier's price list.
Can I use the supplier's SKU as my own?
You can while you have one supplier. When the same product comes from a second supplier with a different code, the catalog gets duplicates, so it is safer to have your own SKU and keep the supplier code in a separate field.
Sources
- GS1, GS1 Company Prefix and the list of GS1 prefixes (prefixes do not identify the country of origin; 200–299 for restricted circulation numbers) — gs1.org.
- GS1 US, how to get a UPC barcode — gs1us.org.
- Google Merchant Center, ID [id] (use SKUs as IDs; do not change an ID) — support.google.com/merchants/answer/6324405.
- Google Merchant Center, GTIN [gtin] (UPC 12 digits, EAN 13 digits) — support.google.com/merchants/answer/6324461.
- Google Merchant Center, MPN [mpn] — support.google.com/merchants/answer/6324482.
Checked on October 31, 2026.
John Smith
Great topic for discussion! I think one way to be original is to use short and memorable words or phrases related to the product. For example, if it is cosmetics, then you can use words that reflect beauty or skin care. What do you think?