---
title: "What is an MPN? Manufacturer part number | Product Metrics"
description: "An MPN (manufacturer part number) is the code a manufacturer gives one product. See when Merchant Center needs it, how it pairs with brand and common mistakes."
canonical: "https://www.productmetrics.io/glossary/mpn"
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

# MPN (manufacturer part number)

An MPN (manufacturer part number) is the code a manufacturer assigns to identify one product among all the products it makes.

## Example

Identifier fields for four products:

| Product | brand | gtin | mpn | identifier_exists |
| --- | --- | --- | --- | --- |
| Trail Runner 2, black, size 42 (resold) | Example Brand | 8712345678906 | TR2-2026-BLK-42 | leave out |
| Replacement filter F20 (no GTIN) | Example Appliances | leave out | F20-0415 | leave out |
| Linen apron, sage (you make it, only you sell it) | Your store name | leave out | APR-LIN-SAGE | leave out |
| Custom-printed T-shirt (one-off) | leave out | leave out | leave out | no |

The first two rows carry the manufacturer’s own codes. The apron is the exception: as its manufacturer and only seller, you use your store name as the brand and an MPN of your choice. The T-shirt has no identifiers, so identifier_exists is no. Illustrative data.

## For one product, and for an account

An MPN is unique only among one manufacturer’s products, so it identifies a product together with its brand. It usually belongs to one variant: Merchant Center notes that each colour or size typically has its own MPN, although apparel sizes often share one.

Merchant Center requires an MPN for every product without a manufacturer-assigned GTIN, and products that have a brand and MPN but are submitted without them may have limited visibility.

Identifiers also decide which shops sell the same product. Competitor Prices treats products as identical when they share a product id, GTIN or EAN. Own-brand products share no identifier with competitors, so it compares them on the dimensions you approve, such as style and colour.

## Common mistake

Putting your own SKU in the mpn field for a product someone else makes. Merchant Center wants the manufacturer’s MPN: no internal SKUs or other store-specific values, and no identifiers made up, guessed or copied from similar products.

## Questions

### What is an MPN number on a product?

Look on the packaging or the manufacturer’s site: it is usually a mix of letters and digits. Merchant Center accepts 1 to 70 characters, and its own example pairs the brand Google with the MPN H2G2-42.

### What is the difference between an MPN, a GTIN and a SKU?

A GTIN is the global number behind the barcode, the same for every shop that sells the product. An MPN is the manufacturer’s code, unique only within that brand. A SKU is the code you create for your own stock, so it differs from shop to shop.

### Is an MPN required in Google Merchant Center?

Only for products without a manufacturer-assigned GTIN. It is optional for products with no clearly associated MPN and for custom-made items such as art or handmade goods. If a product has no GTIN, MPN or brand at all, set identifier_exists to no, and only when you are certain: a product wrongly marked no gets a warning.

## Sources

- [Google Merchant Center Help: MPN [mpn]](https://support.google.com/merchants/answer/6324482)
- [Google Merchant Center Help: Unique product identifiers](https://support.google.com/merchants/answer/160161)
- [Google Merchant Center Help: Identifier exists [identifier_exists]](https://support.google.com/merchants/answer/6324478)

## Keep reading

- [GTIN](https://www.productmetrics.io/glossary/gtin): The barcode number Merchant Center asks for first; the MPN fills in when there is none.
- [Product feed](https://www.productmetrics.io/glossary/product-feed): The data source where the mpn, brand and gtin of every product sit.
- [Google Merchant Center](https://www.productmetrics.io/glossary/google-merchant-center): Where missing or incorrect identifiers show up as warnings and disapprovals.
- [Supplemental feed](https://www.productmetrics.io/glossary/supplemental-feed): A second data source that adds to or overrides attributes in the primary feed.
- [Competitor Prices](https://www.productmetrics.io/competitor-prices): How products are compared when they share an identifier, and when they do not.

---

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

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