How do you create SKU numbers?

How to create SKU numbers? It’s not complicated, but doing it right from the start saves you hours of cleanup later. A good SKU tells anyone in your warehouse exactly what they’re holding without opening a product record.

Warehouses with structured SKU conventions report up to 50% fewer picking errors than those using product names or made-up codes, per WERC benchmarks.

The SKU naming formula

What format should SKU numbers follow?

The most reliable structure for ecommerce:

[CATEGORY]-[PRODUCT CODE]-[VARIANT ATTRIBUTES]

Each segment should be short and predictable. Here’s how it works:

Segment	Purpose	Example	Character length
Category prefix	Groups related items in reports	SHIRT, BAG, ELEC	3-5 characters
Product code	Identifies the base product	CRW (crew neck), TOT (tote)	3-4 characters
Variant attributes	Size, color, pack count	BLK-M, NAV-OS, RED-XL	2-6 characters

Assembled: SHIRT-CRW-BLK-M = crew-neck shirt, black, medium. Total: 15 characters including hyphens.

Step-by-step process

1. List your categories. Group your catalog into 5-10 top-level buckets. Assign each a 3-5 character code (e.g., APRL for apparel, ELEC for electronics).
2. Code each base product. Give every product a short 3-4 character identifier independent of variants (e.g., CRW for crew neck, VNK for V-neck).
3. Define variant attributes. Pick a fixed order for attributes: always color before size. Use standard 2-3 character abbreviations: BLK, WHT, RED for colors; S, M, L, XL for sizes.
4. Assemble and validate. Build a few codes and test them. Can a picker read the SKU on a small label and know what it is? If not, revise the abbreviations.
5. Document the convention. Write your rules in a spreadsheet or wiki before creating your first SKU. Teams that skip this end up with BLK-SHIRT-M for one product and SHIRT-M-BLACK for another.

Rules that prevent problems

Why should you never reuse a discontinued SKU?

• Keep codes 8-12 characters: long enough to encode meaning, short enough for scanner displays and mobile screens
• Uppercase letters only: lowercase l and 1 look identical in most label fonts
• No spaces, slashes, or special characters. They break CSV imports and API calls.
• One unique SKU per variant, not per base product. A red medium shirt and a blue medium shirt are different SKUs.
• Never reuse a discontinued SKU. It corrupts historical sales and inventory reports.
• Reserve a prefix or suffix for bundle SKUs to separate them from components

Common SKU format examples

Structured SKU conventions cut picking errors by up to 50%

Product type	Example SKU	Breakdown
Apparel	APRL-CRW-BLK-M	Apparel, crew neck, black, medium
Electronics	ELEC-CHG-USB-C	Electronics, charger, USB-C
Accessories	ACCS-TOT-NAV-OS	Accessories, tote bag, navy, one-size
Bundle	BNDL-STRT-3PK	Bundle, starter kit, 3-pack
Consumable	FOOD-BAR-CHC-12	Food, bar, chocolate, 12-count

A single base product with 4 colors and 3 sizes produces 12 distinct SKUs. A catalog of 50 base products with similar variant depth hits 600 SKUs fast, which is why a documented convention matters before you start.

If you’re managing SKUs across multiple sales channels, inventory management tools for small business keeps your naming consistent and your counts accurate everywhere. Upzone assigns each SKU to a specific bin location, so clean naming feeds directly into faster picking. Try it free for 14 days — plans start at $79/mo, no credit card required.

Quick Reference

Rule	Why it matters
8-12 alphanumeric characters	Fits label space; reduces scan errors
Uppercase only	Prevents l/1 and O/0 confusion
Fixed attribute order	Makes codes predictable across your whole team
One SKU per variant	Tracks inventory at the right level of detail
Never reuse discontinued codes	Keeps historical reports clean
Document before you start	Prevents format drift as your catalog grows

• A catalog with 50+ products needs a written naming convention before any products go live
• Use the same attribute sequence on every SKU: color before size, always
• Changing SKUs after launch means updating every order record, barcode label, and integration mapping
• Every unique product combination (color + size + bundle) needs its own SKU: 4 colors x 3 sizes = 12 SKUs per base product
• 50% fewer picking errors reported by warehouses using structured SKU conventions versus ad-hoc naming