What Is an MPN on eBay? UK Product Identifiers Guide (GTIN, EAN, UPC, ISBN) 2026

If you sell on eBay UK, you’ll meet a wall of acronyms the moment you create a listing: MPN, GTIN, EAN, UPC, ISBN, ePID. They overlap, they’re easy to confuse, and eBay now requires at least one of them on most new, branded listings — so getting them wrong blocks you from publishing, or buries your item in search.

This guide explains every product identifier a UK eBay seller will encounter in 2026: what each one is, how to find it, when eBay requires it, and how it affects where your listing ranks. The facts here are taken from eBay’s own developer documentation and GS1, the body that issues barcodes — not guesswork.

• MPN = the maker’s part code. Alphanumeric, set by the manufacturer, often (not always) the same as the model number.
• GTIN = the barcode number. It’s an umbrella term: your EAN (13 digits), UPC (12 digits) or ISBN (books) is a GTIN.
• In the UK you’ll almost always use an EAN — the 13-digit barcode on UK/EU retail packaging. A US UPC is also accepted.
• eBay requires identifiers on most new & refurbished branded items. Typically Brand + MPN + a GTIN, depending on category.
• Used, vintage, handmade or one-off items are exempt — set the field to “Does not apply”.
• ePID is eBay-internal and no longer shown on listings — useful for pre-filling a listing, not something buyers search.

MPN stands for Manufacturer Part Number. It’s a unique code the manufacturer assigns to a specific product or part. When a maker releases a new version of a product, it usually gets a new MPN — so the MPN pins down not just the product but the exact variant.

MPNs are frequently identical or very similar to the item’s model number, but not always — so don’t treat them as interchangeable unless you’ve confirmed they match for that specific item. eBay treats the MPN as one half of a pair: it lives next to the Brand field, and eBay’s documentation refers to the two together as BrandMPN.

Where an MPN earns its place is precision. For a part or accessory that fits a range of devices, the MPN is often the only reliable way a buyer can confirm compatibility — two chargers can look identical in photos and have completely different part numbers. Real examples from eBay’s own docs: DSC-RX100/B, ILCZVE10L/B, fcb-ex980sp.

This is the confusion that trips up most sellers, so here it is plainly:

• An MPN is assigned by the manufacturer. It’s their internal part code. There’s no central registry and no fixed length — it’s whatever the maker decided.
• A GTIN is assigned through GS1, the global barcode authority. It’s the number encoded in the black-and-white barcode on the packaging. Per GS1, the GTIN is the number; the barcode is just its visual representation.

So a single product can carry both: a GTIN (its barcode) and an MPN (the maker’s part code) — plus a Brand. eBay wants as many of these as apply, because together they identify the item with near-zero ambiguity.

GTIN is the umbrella term for the family of barcode numbers issued by GS1. It comes in several lengths — GTIN-8, GTIN-12, GTIN-13 and GTIN-14 — and the type you have depends on the product and where it was made. When eBay or GS1 say “GTIN”, they mean “whichever of EAN / UPC / ISBN applies to your item”.

The EAN is the one most UK sellers use. It’s a 13-digit code (a GTIN-13) printed beneath the barcode on UK and European retail packaging. GS1 UK confirms the EAN-13 “works worldwide, including the US” — so if your stock has an EAN, that’s your default GTIN for eBay. eBay validates that any EAN you enter complies with the GTIN-13 standard.

The UPC is the North American equivalent: a 12-digit code (a GTIN-12), the barcode you see on products in US shops. It’s recognised globally and is valid on eBay UK — eBay accepts a UPC that complies with the GTIN-12 / UPC-A standard. The quickest way to tell an EAN from a UPC: count the digits. 13 = EAN, 12 = UPC.

ISBNs are GTINs used specifically for books. Every book and every edition gets its own. They come in two forms: the older 10-digit ISBN-10 and the 13-digit ISBN-13 (which begins 978 or 979). eBay accepts either. If you sell books, the ISBN is effectively required — it’s on the back cover beside the barcode.

A JAN is Japan’s national barcode. Structurally it’s identical to an EAN — a 13-digit GTIN-13 — and eBay validates it against the same standard. You’ll only meet it on Japanese-sourced stock; for everything else, EAN or UPC is what you’ll have.

The ePID is eBay’s own internal catalogue reference. Crucially: it no longer appears on listings and buyers can’t search by it — so it’s not something you optimise for. Where it helps is listing creation: if your item matches a product already in eBay’s catalogue (found via its GTIN or title), eBay can pre-fill the title, specifics and stock image from that ePID, saving you typing them out. Think of it as a behind-the-scenes convenience, not a buyer- facing identifier.

The whole family in one view:

eBay has steadily expanded identifier requirements to improve buyer trust and stop mismatched listings. The current position for UK sellers:

• New & manufacturer-refurbished branded items: eBay generally requires identifiers — typically a Brand, an MPN, and a GTIN (your EAN or UPC). The exact mix is set per category.
• Relisting or revising an old listing: if it doesn’t already carry identifiers, eBay will ask you to add Brand, MPN and GTIN before it’ll let you republish.
• Business sellers: if you’re registered as a business, expect to provide a valid identifier (or the “Does not apply” flag) on essentially everything you list.

Requirements genuinely vary by category, so the authoritative check is always the listing form itself — when you pick a category, eBay shows whether each identifier is required, recommended or not applicable.

Not every item has a barcode, and eBay knows it. Product identifiers are not required for used, collectible, vintage, handmade or one-of-a-kind items — anything that was never assigned a manufacturer code. In those cases:

• Set the GTIN/EAN/UPC field to “Does not apply”.
• If there’s no brand, set Brand to “Unbranded” — eBay explicitly allows this in place of a real brand name.
• If there’s no part number, set MPN to “Does not apply”.

Don’t invent a code to get past the form. eBay rejects junk values — its documentation specifically bans brand entries like “Brand new”, “Made in China”, “See the description below” and “100% compatible with listed model”, plus anything that’s only special characters. “Does not apply” is the correct, accepted answer.

Most identifiers are easier to find than sellers expect:

If you buy stock direct from the manufacturer, the MPN is on the packaging or in the inventory file with your order. Otherwise it’s in the manufacturer’s online catalogue — search the product name on their site and the MPN is usually in the spec block. Remember it may match the model number, but verify before assuming.

Both print as digits directly beneath the barcode on the packaging. Count them: 13 digits is an EAN, 12 is a UPC. No packaging? The manufacturer’s website usually lists the barcode number, and for many products a quick search of the product name plus “EAN” or “barcode” turns it up.

On a book, it’s on the back cover, usually bottom-left beside the barcode, and often repeated on the copyright page inside. A 13-digit ISBN starts 978 or 979.

You don’t hunt for an ePID on packaging — you match it inside eBay. Search eBay’s catalogue by your item’s GTIN, MPN or title; if a catalogue product exists, selecting it attaches the ePID and pulls in the stock specifics. If nothing matches, the item simply isn’t in eBay’s catalogue yet — that’s fine, you list it manually.

1. In the listing form, scroll to Item specifics. The Brand, MPN and GTIN/EAN/UPC fields appear here, flagged required or optional for your category.
2. Enter the GTIN (your EAN or UPC) in the barcode field. eBay validates the format on the spot — a 13-digit EAN must be valid GTIN-13, a 12-digit UPC must be valid GTIN-12 / UPC-A.
3. Fill Brand and MPN. For a multi-variation listing, put the GTIN and MPN on each variation, not just the parent — each colour/size can have its own.
4. If any identifier genuinely doesn’t exist, use “Does not apply” (or “Unbranded” for Brand) rather than leaving it blank or faking a value.

Product identifiers aren’t just a compliance box — they’re a ranking input, in two places:

• On eBay (Cassini): eBay’s search engine uses identifiers to match your listing to the right buyer queries and to group it with the correct catalogue product. A complete, correctly-matched listing is far more likely to surface than a thin one.
• Off eBay (Google & Bing): a valid GTIN lets Google Shopping and organic search confidently identify your product, which can pull your eBay listing into off-site results — a second traffic source you get for free.

The practical takeaway: fill every identifier that applies, use the real values, and put the MPN/model in the title. It’s low-effort and compounds across every listing you run.

Often, but not always. They’re frequently identical, but a manufacturer can use a model number for marketing and a separate, more granular MPN for each specific configuration. Check the manufacturer’s catalogue before treating them as the same value.

Used, vintage, handmade and one-of-a-kind items don’t need a GTIN — set the field to “Does not apply”, and “Unbranded” for Brand if there isn’t one. Don’t fabricate a code; eBay rejects placeholder values.

Use whichever is on your product. In the UK that’s almost always an EAN (13 digits). If your stock is US-sourced and carries a 12-digit UPC, that’s fine too — eBay accepts both. You don’t need to convert one to the other.

Barcodes (GTINs) are issued through GS1 UK, the official body. If you manufacture your own branded products and need retail barcodes, that’s where they come from. If you’re reselling existing branded stock, the GTIN already exists — you just read it off the packaging.

Yes — add every identifier that genuinely applies. More accurate identifiers mean better matching on eBay, better odds of appearing in Google results, and easier stock-keeping when a manufacturer revises a product and issues a new MPN. It’s low effort for a real visibility gain.

• eBay Developers Program — Product identifiers (Trading API User Guide) — valid identifier types and the GTIN/BrandMPN validation rules.
• GS1 — Difference between a GTIN, barcode, EAN and UPC — GTIN as the number vs barcode as the visual; GTIN-12/13 formats.
• GS1 UK — Which barcode should I use? — EAN-13 as the UK retail default; works worldwide including the US.
• International ISBN Agency — ISBN-10 / ISBN-13 and the 978/979 prefixes.

eBay’s category-level identifier requirements change over time and by category. Always confirm against the live listing form for your specific item.