GTIN, MPN and Brand for Google Shopping: What They Are and What to Do Without Them

What is a GTIN, and do you need one to sell through Google Shopping? This guide answers that for online store owners. It explains GTIN, UPC, EAN, MPN and brand in plain terms, what Google Merchant Center asks for, how to get a GTIN, and what to send for own-brand, handmade and custom products that have no barcode.

What is a GTIN?

A GTIN (Global Trade Item Number) is the number printed under a product’s barcode. The barcode is the pattern of lines a scanner reads; the GTIN is the number it carries. Each GTIN identifies one product in one version: a new size, colour, style or pack count gets its own number.

GTINs come from GS1, the organisation behind retail barcodes. A brand owner licenses a block of numbers from GS1 and assigns one to each product. That is why a GTIN tells Google not just what the product is, but whose it is.

To find the GTIN of a product you sell:

• Look at the packaging. It is the number under the barcode, usually 12 or 13 digits.
• Ask your supplier. Manufacturers and distributors include GTINs, often labelled UPC or EAN, in their product data and price lists.
• Check it with GS1. GS1’s company database lookup (opens in a new tab) shows which company a GTIN is licensed to, so you can confirm it belongs to the brand you are selling.

UPC vs GTIN, EAN and the rest

“GTIN” is the umbrella name. UPC, EAN, JAN and ISBN are different formats of it, used in different regions or for different products. A UPC isn’t an alternative to a GTIN: its 12 digits are a GTIN-12. Google accepts all of them in the same gtin attribute, and ignores spaces and dashes.

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A UPC has three parts: the brand owner’s GS1 company prefix (the first 6 to 10 digits), an item reference the brand owner chooses, and a final check digit. Other GTINs follow the same pattern with a different length.

The check digit

The last digit of every GTIN is calculated from the others. It catches typing and scanning errors, and Merchant Center checks it: a GTIN with the wrong check digit is rejected. The calculation is short:

1. Take every digit except the last one.
2. Starting from the right, multiply the digits by 3, 1, 3, 1 and so on.
3. Add up the results.
4. The check digit is what you add to reach the next multiple of 10. If the sum already is one, the check digit is 0.

Take the example UPC 614141000036. Leave out the last digit, 6, and work through 61414100003 from the right:

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The results add up to 54. The next multiple of 10 is 60, and 60 − 54 = 6, so the check digit is 6 and the full number is 614141000036. GS1’s check digit calculator (opens in a new tab) does the same for any length. A correct check digit only proves the number is well formed, not that it belongs to the product.

What is an MPN?

An MPN (manufacturer part number) is the code the manufacturer uses for a product: a model number, part number or style code. It is printed on spec sheets and often on the product itself. Unlike a GTIN, it isn’t standardised: any letters and numbers, up to 70 characters.

Google needs the MPN for products that don’t have a GTIN. When a product has both, send both. Variants usually have their own MPNs, for example one per colour, although clothing sizes often share one.

The MPN must be the manufacturer’s number. If you resell other brands, your own SKU is not an MPN. If you make the product yourself, you are the manufacturer, so your own product code is your MPN.

Brand

Google requires a brand for every product with a clearly associated brand or manufacturer. That includes products you make yourself. It is only optional for products without a clear brand, such as books, films, music and posters.

• Other brands’ products: send the brand shoppers recognise, the one on the product. Not your store name.
• Own-brand and private label products: send your store name or your own brand name.
• Compatible products, such as a third-party phone case: send the brand of the company that made the case, not the phone’s brand.

What Google needs, at a glance

These are the rules from Google’s help pages for gtin (opens in a new tab), mpn (opens in a new tab), brand (opens in a new tab) and identifier_exists (opens in a new tab):

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What happens when an identifier is missing? Google says products with an assigned GTIN that are submitted without one “may have limited visibility”, and a product whose manufacturer GTIN or MPN you leave out could be disapproved. Google’s help page for this issue, once titled “Limited performance due to missing identifiers”, now calls it “Missing or incorrect GTIN”. The fix it gives: add a brand and either a GTIN or an MPN.

Used and vintage products follow the same rule: if the item has a GTIN, send it, and set condition to used. Non-physical items, such as digital downloads, must have a GTIN.

Products without a GTIN: own-brand, handmade and custom

Many small stores sell products that never had a barcode. Google accepts them. Don’t make up a GTIN; send what the product really has:

• Own-brand or private label, no barcode: brand = your store or brand name, MPN = your own product code, no GTIN. Google says store brands often have no GTIN and should send brand and MPN.
• Handmade, one-of-a-kind or custom-made: brand = your store name. If you don’t give the product a code, leave the MPN empty and send identifier_exists as no.
• Vintage and antiques, and books published before 1970: send identifier_exists as no if there is no GTIN or MPN.
• Your own bundles or multipacks of other brands’ products: use the GTIN, MPN and brand of the main product (bundles) or the single product (multipacks). If the manufacturer made the multipack, use the multipack’s own GTIN.
• Personalised or engraved versions of a branded product: keep the manufacturer’s GTIN and say in the title and description that the item is customised.

How to get a GTIN

If you sell products made by others, you don’t need to get GTINs: use the manufacturer’s. You only need your own when you are the brand owner and want barcodes, for example to sell in shops or on marketplaces that require them.

1. Go to GS1 in your country. In the US that is GS1 US (opens in a new tab). Other countries have their own GS1 organisation.
2. License a single GTIN or a GS1 Company Prefix. GS1 US sells single GTINs for stores with only a few products, and company prefixes, renewed every year, for growing ranges. Check the current prices on their site.
3. Assign a number to each product and each variant: every size, colour, style and pack count gets its own GTIN.
4. Print the barcodes on your packaging and enter the numbers in your store.

Common mistakes

• Invented numbers. A made-up GTIN may even pass the check digit, but it doesn’t belong to your brand. Google’s rule is simple: if you’re unsure of a GTIN, don’t submit one.
• Wrong check digit. One mistyped digit, or a number pasted into a spreadsheet that dropped its leading zero, gives an invalid GTIN. Google rejects the value.
• One GTIN for every variant. Each size and colour has its own barcode. Sending the parent product’s GTIN on all of them means Google can’t tell them apart.
• The wrong pack size. A case of 12 has a different GTIN from a single unit. Send the GTIN of what the customer actually buys.
• Your SKU in the MPN field. For products you resell, the MPN must be the manufacturer’s part number. Only use your own code when you make the product yourself.
• A brand that doesn’t match the GTIN. Merchant Center reports “GTIN not related to brand” when the brand you send isn’t the one the barcode belongs to. Use the real manufacturer’s brand.

Two more from Google’s rules: GTINs starting with 02, 04 or 2 are in GS1’s restricted ranges, and those starting with 05, 98 or 99 are coupon codes. Google doesn’t accept either. And don’t send several products for the same country with the same GTIN.

GTIN, MPN and brand in nopCommerce

If your store runs on nopCommerce, the three identifiers already have fields:

• GTIN and Manufacturer part number are in the product’s Product info section.
• Brand comes from the product’s manufacturer. Create brands in Catalog → Manufacturers and assign one to each product; for your own products, create one with your brand name.
• Attribute combinations have their own SKU, GTIN and manufacturer part number, so each size or colour can carry its own barcode.

Our free Merchant Center Feed for Google plugin checks every product before it goes to Google. It holds back products Google would reject and warns about missing brands, GTINs and part numbers. When a GTIN has an invalid check digit, it leaves the GTIN out so the product stays listed while you fix it. It sends each attribute combination as its own item, with its own GTIN.

To find the gaps first, the free StorePulse plugin lists products without a GTIN or part number, with links to edit them. For the rest of the feed setup, see our nopCommerce Google Shopping feed guide.

Frequently asked questions

Next steps

Go through your catalog in three groups. Products from other brands: get the GTIN and MPN from your supplier and set the right brand. Your own products with barcodes: enter the GS1 numbers per variant. Your own products without barcodes: brand and your product code, or identifier_exists = no for one-of-a-kind items.

Need supplier data imported into your store, or a feed that handles a special case? We build nopCommerce plugins and integrations. Send what you sell and where to contact@cartenvo.com.