How Google Shopping Ads Work: From Your Feed to the Auction

Google builds a Shopping ad from your product data rather than from ad text you write. A product appears only if it passes four checks. Your feed sends it to Merchant Center, Merchant Center approves it, a campaign includes it, and it wins the auction for a search. In 2026, two campaign types show Shopping ads: Standard Shopping and Performance Max. In a sample of flagged products from our data, the most common product issue in Google Ads points to the third check: “not eligible in any campaign”.

What is a Google Shopping ad?

A Shopping ad shows a product photo, its title, its price and your store name. Google creates it from the product data in your Merchant Center account, so you never write a separate ad for each product. According to Google Ads Help (About Shopping ads), Shopping ads use that product data, not keywords, to decide how and where to show your ads. You choose which products a campaign covers, and Google matches them to searches.

Where the ads appear depends on the campaign type. The same Help page lists four places for a Standard Shopping campaign, including the Shopping tab and Google Images. Performance Max adds other formats, such as YouTube and Gmail.

In a Standard Shopping campaign, you pay per click. The page adds one more rule: in countries covered by the Comparison Shopping Service (CSS) programme, you take part in Shopping ads through one or more CSSs.

In most stores in our data, Shopping ads now run inside Performance Max, which is the wider subject of our Performance Max guide for online stores. This article covers one narrow part of it: the path of a single product.

How does a product get from your feed to a Shopping ad?

A product passes four checks in order. If it fails one, it never reaches the next.

1. The feed delivers it to Merchant Center. Your product feed submits each product with its title, price, availability, image and identifiers. The Google Ads API documentation (Shopping Ads overview) names two ways to send products: a product feed, or individual products sent through the Content API.
2. Merchant Center approves it. According to the same overview, only approved products become available to use with Google Ads. Google’s troubleshooting guide (Monitor and optimize your Shopping campaigns) gives examples of data that can lead to disapproval: a price in the feed that doesn’t match the landing page, or incorrect availability.
3. A campaign includes it. You need to link Google Ads to your Merchant Center account. A campaign then takes products from that account, can limit them to one feed label, and splits them into product groups that include or exclude products. A Standard Shopping campaign can narrow the set further with an inventory filter.
4. It wins the auction. Being in a campaign makes a product eligible, nothing more. For each search, Google runs an auction among eligible products. Your bids or targets, your budget and the competing ads all affect whether your product appears.

Google Ads keeps its own status for each product: eligible, eligible with limits, or not eligible (ProductStatus in the Google Ads API reference). The reference page for ShoppingProduct adds that the status and its list of issues can take up to 24 hours to update after a change. The same page confirms the inclusion rule behind the third check: the Merchant Center ID in the campaign settings, optionally narrowed to one feed label.

Product groups are an easy place to lose a product without noticing. Google’s API documentation calls them listing groups (Create shopping listing groups). It describes them as a tree that can include or exclude products and says ads serve only once a valid tree exists.

Which campaign types can show Shopping ads in 2026?

The About Shopping ads page in Google Ads Help names two: Performance Max with a Merchant Center feed, and Shopping campaigns. A Shopping campaign, called Standard Shopping in Google Ads, shows only Shopping formats unless you add AI Max to it. Performance Max shows them alongside other formats. Other campaign types, such as Demand Gen and Video, can use the same feed, but they show products on their own surfaces.

The sources for each row:

• Standard Shopping. The places it shows come from About Shopping ads. The Google Ads API guide (Create a Shopping campaign) adds that Standard Shopping campaigns can’t target the Display Network.
• Performance Max. Google’s guide for retail campaigns (Performance Max for online sales with a product feed) says the campaign needs a linked Merchant Center account and at least one listing group. Adding an asset group enables the Shopping channel, and more formats need more assets: text, images or video.
• Smart Shopping. Google upgraded these campaigns to Performance Max automatically, on a schedule set for July to September 2022 (Get ready for Smart Shopping and Local campaign upgrades). After the upgrade, you can no longer create a new one.
• Demand Gen and Video. The Shopping Ads overview lists both among the campaign types that use a Merchant Center feed. Demand Gen runs on YouTube, Discover, Gmail and Google Maps (Demand Gen in the Google Ads API). Video campaigns show on YouTube and on Google video partner sites and apps (Video campaigns in the Google Ads API).

One 2026 change affects Standard Shopping. On 30 April 2026, Google announced AI Max for Shopping (Adapt your Shopping campaigns to modern Search with AI Max), an upgrade you opt into. It can write ad text for Shopping ads, send clicks to other pages of your site through Final URL expansion, and pick a text ad or a Shopping ad for each search. You keep your product targeting, and if you switch off Final URL expansion, delivery stays limited to Shopping ads.

When two campaigns include the same product

When two of your campaigns include the same product, a rule decides which campaign serves it.

• Two Standard Shopping campaigns. Campaign priority decides (Use campaign priority for Standard Shopping campaigns): every campaign starts at Low, and you can raise it to Medium or High. The higher-priority campaign bids even if a lower-priority one has a larger bid. When it runs out of budget, the next one bids. At equal priority, Google uses the highest bid.
• Performance Max and Standard Shopping in the same account. Until October 2024, Performance Max took priority automatically. On 23 October 2024, Google announced a new rule: “Ad Rank will determine which campaign serves an ad” (New Performance Max features: Assets experiments, video enhancements, and more). Smarter Ecommerce, a vendor of Shopping tools, still describes the same rule in its January 2026 guide (How to run Google Shopping alongside Performance Max in 2026).

Which type your store should run, and when to keep both, is a separate decision. We cover it in Performance Max vs Standard Shopping.

Feed errors are rare; products stall at campaigns and the auction

We checked where products stop between the feed and the ad in our own data. These are observations across stores, not an experiment.

Product issues concentrate in a few catalogues. Google Ads lists at least one product issue for 55.9% of the 5,744,507 products in our stores’ catalogues. Yet among the 142 stores with at least 100 products, the median store has 0.0% of its catalogue flagged. In 109 of them, less than 1% of the catalogue has any issue (GetProfit data, 142 stores, catalogue snapshots in a data bank collected in August 2026). A few very large catalogues hold most of the flagged products.

The most common issue is about campaigns. In a sample of 400,000 flagged products from the same data, 263,483 carried “not eligible in any campaign”, 209,328 were out of stock and 38,032 had no shipping set for the country. Classic data errors, such as a missing required attribute or an image that is too small, counted in the hundreds in that sample.

The two leading issues reflect campaign and stock decisions rather than broken data. The first one describes the campaign check: the product is in Merchant Center, but no campaign can serve it. We explain the “not eligible in any campaign” issue and how to clear it separately.

55.0% of products got no ad spend. In our study of 1.4 million products across 130+ stores over 13 months, 45.0% of products received ad spend. Of all products, 7.9% sold and took 78.1% of spend, while 37.1% got spend without a single sale and took the other 21.9%. The remaining 55.0% got no spend at all. Of the 1,196,357 products that started the period with zero spend, 74.1% never received a single impression in 13 months.

For most stores, Shopping ads mean Performance Max. Performance Max runs in 141 of 146 stores in our data and takes a median 95.7% of their ad budget. Standard Shopping runs in 74 of them and takes a median 6.5% of budget where it runs (GetProfit data, 146 stores, June 2025 – June 2026). So for most stores in our data, the first place to look for a missing product is the listing groups of a Performance Max campaign.

Which of the never-shown products deserve a way back is its own question. We look at it in why most products get no impressions.

A worked example: where 1,800 products go missing

Example store, not client data.

A tableware store has 3,000 products in its feed. It spends 40,000 a month and gets 180,000 in revenue, so its ROAS (revenue divided by spend) is 4.5. Here is where its products stop over that month.

So 1,800 products, 60% of the catalogue, never got an impression. Assortment coverage, the share of the catalogue that got impressions, is 40%. A ROAS of 4.5 describes only the products that got impressions.

Fixing every Merchant Center issue brings back at most 150 products. Reopening one excluded product group returns 450 products to the campaign at once. The 1,200 products that are included but never shown depend on bids, targets and budget.

What to check when a product never shows

1. Read the product’s status in Merchant Center. If it is disapproved or out of stock, fix the data or the stock first. A product needs approval before any campaign setting can help it.
2. Check its status in Google Ads. The Product status column on the Products page shows whether it is eligible, eligible with limits, or not eligible. Allow up to 24 hours after a change before you judge it.
3. Find the campaign that should include it. Check the linked Merchant Center account, the feed label, the inventory filter and the product groups. An excluded group or a feed label that doesn’t match keeps the product out.
4. If two campaigns include it, work out which one serves. Between Standard Shopping campaigns, campaign priority decides. Between Performance Max and Standard Shopping, Ad Rank decides.
5. If it is included but has no impressions, look at the auction. For a Shopping campaign with low impressions, Google’s troubleshooting guide names common causes: product data problems in Merchant Center, restrictive bidding strategies, or a campaign still in its learning phase.
6. Count the whole catalogue, not one product at a time. The number of products stuck at each check tells you which one to fix first.

The portal’s Assortment section runs this count for the whole catalogue. It walks every product through the stages from the feed to sales, counting impressions, spend and sales over 90 days. It also keeps two reasons apart: products in no campaign at all, and products in a campaign that never got an impression.

How much of the catalogue reached sales — and what the rest is doing. Sign in with Google Ads. The portal changes nothing without your consent.

Break down your catalogue →

Sources

• About Shopping ads — Google Ads Help: Shopping ads use Merchant Center product data, not keywords; where Standard Shopping and Performance Max show them; cost per click in Standard Shopping; CSS programme countries. Checked 2 October 2026.
• Monitor and optimize your Shopping campaigns — Google Ads Help: data that can lead to disapproval; the Products page and its Product status column; common causes of low impressions. Checked 2 October 2026.
• Use campaign priority for Standard Shopping campaigns — Google Ads Help: Low, Medium and High priority and how they decide the bid; inventory filter. Checked 2 October 2026.
• New Performance Max features: Assets experiments, video enhancements, and more — Google Ads Help, 23 October 2024: Ad Rank decides between Performance Max and Standard Shopping for the same products. Checked 2 October 2026.
• Shopping Ads | Google Ads API — products reach Merchant Center by feed or Content API; only approved products are available to Google Ads; campaign types that use a Merchant Center feed. Checked 2 October 2026.
• ShoppingProduct | Google Ads API — how a campaign includes products; the list of issues affecting whether a product can show in ads; status and issues can take up to 24 hours to update. Checked 2 October 2026.
• ProductStatus | Google Ads API — the three product statuses: eligible, eligible with limits, not eligible. Checked 2 October 2026.
• Create shopping listing groups | Google Ads API — product groups include or exclude products; ads won’t serve without a valid tree. Checked 2 October 2026.
• Create a Shopping campaign | Google Ads API — no separate ad per product; no Display Network for Standard Shopping. Checked 2 October 2026.
• Performance Max for online sales with a product feed (retail) | Google Ads API — linked Merchant Center, at least one listing group, the asset group enables the Shopping channel, more formats with more assets. Checked 2 October 2026.
• Demand Gen | Google Ads API — Demand Gen surfaces: YouTube, Discover, Gmail, Google Maps. Checked 2 October 2026.
• Video campaigns | Google Ads API — Video campaigns show on YouTube and Google video partners. Checked 2 October 2026.
• Get ready for Smart Shopping and Local campaign upgrades — Google blog, 27 January 2022: automatic upgrade of Smart Shopping to Performance Max from July to September 2022. Checked 2 October 2026.
• Adapt your Shopping campaigns to modern Search with AI Max — Google blog, 30 April 2026: AI Max for Shopping announced, its three features. Checked 2 October 2026.
• How to run Google Shopping alongside Performance Max in 2026 — Smarter Ecommerce (a Shopping tools vendor), January 2026: Performance Max and Standard Shopping compete on Ad Rank. Checked 2 October 2026.
• GetProfit data: catalogues of 142 stores with at least 100 products, catalogue snapshots in a data bank collected in August 2026 — share of products and of each store’s catalogue with at least one product issue in Google Ads; the most common issues in a sample of 400,000 flagged products.
• GetProfit data: 146 stores, June 2025 – June 2026 — campaign types by number of stores and median share of budget.
• GetProfit study of 1,404,808 products, 130+ stores, 13 months — products with and without ad spend, products that never received an impression.