Google uses three identifiers to work out exactly which product you are selling: GTIN, MPN and brand. Which ones you need depends on whether the product has a manufacturer barcode. This guide explains each one and what to send for products that have none.
The three identifiers
A GTIN is the number behind the barcode. An MPN is the part number the manufacturer assigns. Brand is the name shoppers recognize the product by.
| Identifier | What Google's help pages say |
|---|---|
| GTIN | Submit it for any product with a manufacturer-assigned GTIN |
| MPN | Required for products that do not have a manufacturer-assigned GTIN |
| Brand | Required for each product with a clearly associated brand or manufacturer |
Google lists brand as optional for products without a clear brand, such as movies, books, music and posters.
GTIN formats Google accepts
The GTIN field accepts 8, 12, 13 or 14 digits, and must include a correct check digit. Each variant, such as a size or color, should carry its own GTIN.
- UPC: 12 digits, used in North America
- EAN: 13 digits, used in Europe
- JAN: 8 or 13 digits, used in Japan
- ISBN: 13 digits for books, with ISBN-10 converted to ISBN-13
- ITF-14: 14 digits, for multipacks
If you make the product yourself
Private-label and store-brand products often have no GTIN. Google's guidance is to leave GTIN out and send brand and MPN instead. If you are the manufacturer and the only seller, and there is no official brand, Google says to use your store name as the brand and to include an MPN of your own choosing.
- Brand: Your store name
- MPN: A unique identifier you assign
- GTIN: Left blank
Custom, handmade and vintage items
Google has an attribute called identifier_exists for products that have no identifiers at all. It is meant for custom or one-of-a-kind goods, such as handmade items and art, and for products made before GTINs existed, such as antiques. Google says to set it to no only when you are certain no identifier was assigned, and that a product gets a warning if there is evidence one exists.
On Shopify, the help page for the Google & YouTube channel says to add the barcode in the Inventory section of the product. For products without barcodes, it says to add the brand name and MPN in the channel.
What not to do
Google repeats the same rule on all three help pages: only submit a value you are sure is correct. A product that has a GTIN or MPN but is submitted without it could be disapproved.
- ❌ A made-up or guessed GTIN
- ❌ One GTIN reused across different variants
- ❌ GTINs from the restricted or coupon prefix ranges
- ✅ The manufacturer's real GTIN, when one exists
If you are seeing the missing GTIN warning specifically, see the GTIN warning guide.
Doing this at scale
FeedFix checks every product against Google Merchant Center and Meta Catalog rules and scores each one from 0 to 100 per channel. It drafts compliant title and description rewrites you review as before/after diffs, with bulk apply and an audit log of every change. See FeedFix.