How many custom labels can I use in Google Merchant Center?

You have five custom label fields (custom_label_0 through custom_label_4). Each can hold one value per product, and you can have up to 1,000 unique values per label attribute across your entire feed.

Do custom labels affect my product's search ranking or approval status?

No. Custom labels are only used for campaign segmentation in Google Ads. They have no effect on whether your products are approved or how they rank in Shopping results.

Can I use custom labels without a supplemental feed?

Yes. You can add custom_label_0 through custom_label_4 columns directly to your primary feed. A supplemental feed is useful when you want to update labels independently from your main feed on a different schedule.

Google Merchant Center Custom Labels Guide 2026

Custom labels are one of the most underused features in Google Merchant Center. They let you tag products with any value you choose, then use those tags to control bidding in your Shopping campaigns. Done well, they can significantly improve your return on ad spend.

What Are Custom Labels?

Custom labels (custom_label_0 through custom_label_4) are five additional attributes you can add to any product in your feed. Unlike Google's required attributes (title, price, GTIN), custom labels are entirely up to you. You define what they mean. Google uses them only when you set up campaign-level product groupings in Google Ads.

What to Use Custom Labels For

The most common use cases:

Margin tiers: Tag products as "high-margin," "medium-margin," or "low-margin." You can then bid more aggressively on high-margin items and scale back on products that barely cover costs.

Sale status: Tag products that are currently on promotion. Set a higher bid on sale items to capitalize on their improved price competitiveness, then remove the tag when the sale ends.

Seasonality: Tag products by season (summer, winter, holiday). Use this to ramp bids before peak periods and reduce spend on out-of-season inventory.

Stock level: Tag products by availability tiers ("in-stock," "low-stock," "clearance"). Pause bidding on nearly-out-of-stock items automatically by feeding this from your inventory system.

Best sellers: Tag your top 20% of products by conversion rate. These often deserve a dedicated campaign with higher bids and more granular negative keyword management.

How to Add Custom Labels to Your Feed

Add a custom_label_0 column to your spreadsheet or data feed. In each row, enter the value you want for that product. Values are free text strings. Keep them consistent (always "high_margin" not sometimes "High Margin") so your campaign groupings work reliably.

If you manage labels separately from your main product data, create a supplemental feed in Merchant Center that contains only your product IDs and custom label columns. Supplemental feeds can be refreshed on a different schedule from your primary feed.

Common Mistakes with Custom Labels

Too many unique values: if you assign a different label to every product, you cannot group them usefully in campaigns. Aim for three to ten distinct values per label attribute.

Not keeping labels current: a "sale" label on a product that is no longer on sale inflates bids without the corresponding price advantage. Build an automated process to update labels when prices or stock change.

Using labels as a substitute for categories: custom labels work best for campaign-management signals (margin, seasonality, velocity), not for product classification. Use Google product categories for the latter.