Google Ads Optimization: How to Edit GMC Custom Labels in Shopify
Learn how to use Shopify Metafields to map Google Merchant Center Custom Labels for more granular Google Shopping ad targeting and improved ROAS.
Background: Why Do You Need Custom Labels?
In previous articles, we briefly mentioned some use cases for Custom Labels in Google product feeds. The main purpose is to help you filter and target specific products more conveniently and flexibly in Google Ads.
For example:
- You only want to advertise certain products, not others
- You want to set different bidding strategies based on profit margins
- You want to create separate ad groups for seasonal or promotional items
All these scenarios can be easily handled with Custom Labels.
Core Principle
This leverages the mapping functionality of Shopify Metafields. You simply need to create the appropriate Metafield in your Shopify admin and ensure it maps to your GMC feed data. When the system syncs the feed via API, it will automatically capture these custom labels.
Step-by-Step Implementation
Create the Metafield Definition
Let's use Custom Label 3 as an example (Google provides 5 label slots from 0-4; choose based on your needs):
- Go to Shopify Admin → Settings → Custom Data → Products
- Click "Add definition"
- Name: Enter
custom label 3(not critical, just for admin identification) - Namespace and key: Enter
mm-google-shopping.custom_label_3(critical - this is the mapping key) - Type: Select Single line text
- Save
Add Custom Label Values to Products
Once you've created the Metafield definition, you can add Custom Label values to each product:
- Go to the product edit page
- Find the Metafield field you just created at the bottom
- Enter your desired label value, such as:
high-margin(high-profit products)seasonal(seasonal products)bestseller(best-selling items)promotion(promotional items)exclude(exclude from advertising)
Wait for Data Sync
After saving the product, Shopify will automatically sync the Metafield data to Google Merchant Center. It typically takes 30-60 minutes for updates to appear in GMC.
You can check the Products page in GMC to see if the Custom Label field has been successfully captured:
Use Custom Labels in Google Ads
Once the data has synced, you can leverage these Custom Labels for granular targeting in Google Ads:
- Go to Google Ads dashboard
- Create or edit a Shopping campaign
- At the Product Group level, select "Custom Label" as the subdivision dimension
- Filter and adjust bids based on your label values
Common Use Cases
Here are some practical Custom Label strategies to help you manage your ad campaigns more effectively:
Use Case 1: Tiered Bidding by Profit Margin
| Custom Label | Description | Bidding Strategy |
|---|---|---|
| high-margin | High-profit products (more than 50% margin) | Increase bids by 20-30% |
| mid-margin | Medium-profit products (30-50% margin) | Standard bidding |
| low-margin | Low profit products (profit margin under 30%) | Reduce bids or exclude |
Use Case 2: Product Performance Classification
bestseller: Store best-sellers, maintain high exposurenew-arrival: New products for testingclearance: Clearance items for volume salesexclude: Products not to advertise or with limited exposure
Use Case 3: Seasonal/Event Marketing
summer-sale: Summer promotionsblack-friday: Black Friday exclusivesholiday: Holiday gift items
Advanced Tips
Bulk Editing Custom Labels
If you have many products, use Shopify's bulk editing feature:
- Go to the product list
- Select the products you want to edit
- Click "Bulk edit"
- Add the Metafield column and fill in values
Combining with Feed Rules for Automation
In GMC, you can also combine Feed Rules to automatically assign Custom Labels based on other fields, enabling smarter product grouping.
Important Notes
- Custom Label values are case-sensitive; maintain consistency
- Each product can only have one Custom Label value (per label slot)
- Allow 30-60 minutes for changes to sync to GMC
- Ensure GMC has successfully captured the data before using in Google Ads
Q&A - Frequently Asked Questions
Summary
By combining Shopify Metafields with GMC Custom Labels, you can achieve:
- More granular product grouping
- Smart bidding based on profit margins
- Flexible inclusion/exclusion strategies
- Quick adjustments for seasonal/event marketing
This technique is simple to set up but is a fundamental part of Google Shopping ad optimization. Every independent store seller should master and apply it.
