Quick answer — how to generate a SKU
A SKU (Stock Keeping Unit) is a short alphanumeric code you assign to each distinct product or variation to track stock and sales. To generate one, combine a few meaningful parts — a category or brand code, the variation (size, colour), and a sequential number with leading zeros — joined by a single separator, e.g. TSHIRT-BLK-M-001. Keep it short, uppercase, consistent in length, and free of spaces and ambiguous characters. The generator above builds these in bulk for free.
What is a SKU?
SKU stands for Stock Keeping Unit. It is an internal code you create to identify a single, sellable variation of a product — say a medium black t-shirt as opposed to a large white one. Unlike a barcode, a SKU is yours: you decide the format, and it never has to match anyone else's. Good SKUs make stock counts, reorders, picking, and profit reporting fast because every product has one unambiguous label.
On eBay, your SKU lives in the “Custom label (SKU)” field on a listing. It is shown to you, not buyers, and it flows through to your orders, reports, and bulk-listing files — which is exactly why a consistent scheme pays off once you have more than a handful of listings.
How to generate SKU numbers — 5 rules
The fastest way is to design a pattern once and apply it to everything. Build each SKU from ordered parts:
- Lead with a meaningful code. A short brand or category abbreviation (NIKE, TEE, BOOK) so you can read a SKU at a glance.
- Add the variations that matter. Size, colour, or model — one segment each. The generator above expands every combination into its own SKU.
- End with a sequential number, zero-padded. Use a fixed width (001, 002 … 010) so codes sort correctly and stay the same length.
- Pick one separator and one case. A single dash or underscore, all uppercase. Mixing styles is the most common cause of duplicate or mistyped SKUs.
- Keep it short and unambiguous. Avoid spaces, slashes that clash with file systems, and characters that look alike — 0/O, 1/I/l.
SKU format examples
Common patterns UK sellers use. Pick whichever maps to how you actually buy and store stock:
| Pattern | Example SKU | Good for |
|---|---|---|
| BRAND-COLOUR-SIZE-NUMBER | NIKE-BLK-M-001 | Clothing & footwear with variations |
| CATEGORY-NUMBER | BOOK-0042 | Media, simple sequential stock |
| SUPPLIER-DATE-NUMBER | AC-2606-014 | Wholesale / job lots by intake batch |
| TYPE-MODEL-CONDITION | PHN-IP13-USED | Refurb tech & graded goods |
SKU vs barcode, UPC/EAN and MPN
These get muddled constantly. A SKU is your own internal code. A UPC or EAN is a global barcode number (a GTIN) that identifies a product universally across retailers. An MPN is the manufacturer's part number, set by the maker, not you. Your SKU can sit alongside all of them — it is the label your own systems use. If you sell branded goods on eBay, see the difference explained in what an MPN is on eBay UK.
What makes a good SKU (and what to avoid)
Do
- Keep every SKU a similar length
- Use leading zeros so numbers sort properly
- Encode things that never change (category, brand)
- Make them readable, so you spot the product without a lookup
Avoid
- Spaces or symbols that break CSV and file names
- Encoding price or cost — those change, the SKU shouldn't
- Reusing a retired SKU for a different product
- Ambiguous characters: 0/O and 1/I/l
Why SKUs matter for eBay profit
A SKU is the hook everything else hangs on. Once each product has a stable code, you can answer the only question that matters: what does this item actually make after fees? That means subtracting the eBay selling fees, postage, and what you paid for the stock — per SKU, every sale.
That is what DashVue's per-item profit reports do: they read your eBay sales, match cost of goods and real postage to each SKU, and show net margin by product. Generate your SKUs here, then let DashVue tell you which ones are worth reordering. Check the headline numbers first with the free eBay fee calculator.
Common questions
How do I generate a SKU number?
Decide on a pattern — usually a category code, any variations, and a zero-padded sequence number — then apply it consistently. The tool above does this in bulk: add your segments, choose a separator and case, and copy or export the result. There is no “official” SKU format; the best one is whatever you'll keep using.
Are SKUs case sensitive?
Treat them as if they are. Most systems compare SKUs as plain text, so tee-001 and TEE-001 can be read as two different products. Picking one case (uppercase is the convention) and sticking to it avoids accidental duplicates.
How long should a SKU be?
Short enough to type and scan, long enough to be unique — most sellers land around 8–20 characters. The priority is consistency: keep them a uniform length so they line up in reports and exports.
Is this SKU generator free?
Yes — completely free, no account, and nothing leaves your browser. The codes are generated on your device.