---
title: "What is a GTIN? Meaning and lengths | Product Metrics"
description: "A GTIN (Global Trade Item Number) is a unique number that identifies a product, usually shown as a barcode. See its lengths, an example and how Google uses it."
canonical: "https://www.productmetrics.io/glossary/gtin"
pageType: article
language: en
publisher: "Product Metrics"
author: "Berend Vrakking"
datePublished: 2026-10-07
dateModified: 2026-10-07
---

> Content index: https://www.productmetrics.io/llms.txt

# GTIN (Global Trade Item Number)

A GTIN (Global Trade Item Number) is a unique number that identifies a product that can be priced, ordered or invoiced, usually shown as a barcode.

## Example

One product with its identifiers:

| Attribute | Value |
| --- | --- |
| id | TR2-BLK-42 |
| title | Trail Runner 2, black, size 42 |
| brand | Example Brand |
| gtin | 8712345678906 (13 digits) |
| mpn | TR2-2026-BLK-42 |

The id is the code you chose for your own stock. The GTIN is the number the product carries wherever it is sold, and the MPN is the manufacturer’s own part code. Illustrative data.

## For one product, and for an account

One GTIN per product, shared by every shop that sells it. The manufacturer part number (MPN) is a different identifier: Google describes it as one that “uniquely identifies the product with its manufacturer”, and Merchant Center asks for it when a product has no manufacturer GTIN.

Google recommends a GTIN for every product that has one assigned by the manufacturer. Store brands and customised items may not have one, which matters when you compare prices: a competitor’s own-brand product carries a different number. Competitor Prices therefore compares own-brand products on the dimensions you approve instead of on GTIN.

## Common mistake

Borrowing a GTIN from a similar product to fill the column. Google says to provide a GTIN only when you are sure it is correct, and to leave it out when in doubt.

## Questions

### Is a GTIN always 14 digits?

No. GS1, the organisation that issues GTINs, says they can be 8, 12, 13 or 14 digits long. Google Merchant Center lists UPC as 12 digits, EAN as 13, JAN as 8 or 13, ISBN as 13 and ITF-14, used for multipacks, as 14.

### Is a GTIN the same as a barcode?

No. The GTIN is the number, and the barcode is the printed symbol that carries it so a scanner can read it. UPC and EAN are formats of GTIN, and people often use the three words interchangeably.

### Are SKU and GTIN the same?

No. A GTIN is a universal identification number issued by GS1, so every seller of the same item uses the same one. A SKU is a code you create yourself to track your own stock, so two shops selling the same item will have different SKUs.

## Sources

- [Google Merchant Center Help: GTIN [gtin]](https://support.google.com/merchants/answer/6324461)
- [Google Merchant Center Help: Unique product identifiers](https://support.google.com/merchants/answer/160161)
- [GS1 US: What is a GTIN?](https://www.gs1us.org/upcs-barcodes-prefixes/what-is-a-gtin)

## Keep reading

- [Google Merchant Center](https://www.productmetrics.io/glossary/google-merchant-center): Where the gtin attribute sits in each product row.
- [Product feed](https://www.productmetrics.io/glossary/product-feed): The file or data source that carries the GTIN of every product.
- [Supplemental feed](https://www.productmetrics.io/glossary/supplemental-feed): Google lists adding a missing GTIN as something a supplemental feed can do.
- [Competitor Prices](https://www.productmetrics.io/competitor-prices): How own-brand products are compared when no GTIN is shared.
- [Product Segmentation](https://www.productmetrics.io/product-segmentation): See each product in one of six segments, by volume and return.
- [What is Google Merchant Center? An advertiser’s guide](https://www.productmetrics.io/blog/what-is-google-merchant-center): Where product identifiers such as the GTIN are submitted.
- [How to track competitor prices for Google Shopping](https://www.productmetrics.io/blog/how-to-track-competitor-prices-google-shopping): Match the same product across shops by its GTIN.

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Written by Berend Vrakking, founder of Product Metrics. Last updated 2026-10-07.

HTML version: https://www.productmetrics.io/glossary/gtin