How Google Shopping ads work
Shopping ads are product ads. Someone searches for a product and sees a row of images with price, retailer name and sometimes ratings or a promotion. Shopping ads appear in the main results, on the Shopping tab and in Google Images, and through Performance Max also on YouTube, Gmail, Discover and the Display Network.
The key difference from search campaigns: you do not bid on keywords. Google reads your product data, such as title, description, category, brand, GTIN and price, and decides which searches each product is relevant to. The same auction then applies as elsewhere in Google Ads: your bid, expected relevance and the quality of your data decide whether and where you appear. You pay per click.
Products in Merchant Center can also show in free listings without any ad budget. Worth having as a base, but not a replacement for paid visibility in competitive categories.
Merchant Center and the feed: where Shopping is won
In Shopping, the feed is your keyword list, your ad copy and your targeting all at once. No bidding strategy can rescue a weak feed. Google documents every attribute in its product data specification; in practice, these parts make the difference:
- Product titles. They largely decide where you appear. Put the words shoppers actually use first: brand, product type, key attribute, size or colour.
- GTIN, brand and MPN. These let Google identify the exact product. Missing or wrong identifiers limit reach.
- Google product category and product type. A logical classification helps Google and makes campaigns by product group possible.
- Images. A clear product photo on the main image, without text or promotional overlays.
- Price, availability and delivery. These must match your website exactly. Outside the US and Canada, Google expects the price to include VAT, so the feed should show what a UK shopper actually pays.
- Custom labels. Five free fields you can use for margin band, bestseller status, season or stock level. They are the basis for steering on profit.
Merchant Center and Google Ads should both be registered to your company. We work through access from our manager account, so your feed, history and data always stay with you.
Shopify, WooCommerce and other platforms
How the feed reaches Merchant Center depends on your platform, and each route has its own weak points.
- Shopify. Google's sales channel app syncs products to Merchant Center quickly. It works, but titles and attributes come straight from your product pages, variants can multiply, and custom labels usually need extra work. Many Shopify shops get better Google Shopping ads once titles are written for searchers rather than for the shop menu. Our Shopify SEO page covers the same product data from the organic side.
- WooCommerce and Magento. Usually a plugin or extension generates the feed. Check that it handles variants, sale prices and stock correctly, and that it updates often enough.
- Feed tools. For larger catalogues, a feed management tool lets you rewrite titles, fill gaps and add labels with rules, without touching the shop itself.
Whatever the route, product IDs in the feed must match the IDs your tracking reports at purchase, or dynamic remarketing and some reporting will not line up.
Standard Shopping or Performance Max?
Since Smart Shopping was folded into Performance Max, retailers choose between two campaign types for products. Performance Max uses your feed plus creative assets and distributes budget across all Google channels itself. Standard Shopping shows only product ads and gives more direct control.
Google has added more controls to Performance Max over time, such as brand exclusions, negative keywords and channel reporting. It remains a system that decides for itself, and it is only as good as the conversion data you give it. For most shops the question is how to combine the two: Performance Max for the broad catalogue, Standard Shopping for products you want to steer tightly or test, and a search campaign for your brand and key product categories.
| Aspect | Standard Shopping | Performance Max |
|---|---|---|
| Where ads appear | Search results, Shopping tab, Images | All Google channels: Search, Shopping, YouTube, Display, Gmail, Discover, Maps |
| What you need | Product feed and budget | Product feed plus text, images and ideally video |
| Control | Bids per product group, negatives, campaign priority | Goals and signals; Google allocates budget |
| Insight | Search terms and results per product | Broader, supplemented by channel and placement reports |
| Suits | Smaller budgets, testing, tight margin control | Enough conversions, a strong feed and assets, a broad range |
| Main risk | Manual work; missing demand outside Shopping | Budget flowing to brand traffic or cheap placements that flatter results |
A structure that steers on margin
The most common Shopping mistake is every product in one campaign with one ROAS target. Budget then flows to whatever sells easily, even when it earns little. Group products by what they can afford to cost instead.
- Margin bands. High-margin products can carry a lower return target than thin-margin ones, but only if they sit apart, using custom labels.
- Bestsellers separately. Stops a few winners consuming the whole budget and shows what the rest of the range does.
- Products without impressions. Part of every catalogue gets little or no visibility. A separate campaign gives those products a fair test, or proves they do not deserve ad spend.
- Brand and non-brand apart. People searching your shop name would often have found you anyway. Keep that traffic separate so results do not look better than they are.
- New customers. The new customer acquisition goal lets you value first-time buyers above returning ones, provided you have a reliable customer list or tracking.
ROAS, break-even ROAS and profit
ROAS, return on ad spend, is ad revenue divided by ad cost. A ROAS of 400% means each pound on ads produced four pounds of revenue. It is the number Google works with when you set a target ROAS. The trouble is that revenue is not profit.
Work out your break-even ROAS first
A rough floor is 1 divided by your gross margin. At a 40% gross margin, break-even ROAS is 1 ÷ 0.40 = 250%. Below that you lose money on every sale before delivery, payment fees, returns and your own time are counted. Calculate on revenue excluding VAT and use the same definition in tracking and targets.
Steering on profit
Some retailers go a step further and report gross profit per order to Google instead of revenue, so the system optimises for what you keep. Routes range from cost-of-goods data in reporting to sending profit values through server-side tracking. What is feasible depends on your platform and whether reliable cost prices exist per product. Our page on Google Ads conversion tracking explains the technical side.
Returns count
In categories with high return rates, such as fashion, factor returns into your target, or you will optimise towards orders that come back.
Avoiding disapprovals and Merchant Center suspensions
A suspended Merchant Center account means every product ad stops. It happens to well-run shops too. The usual causes:
- Price or availability differs between feed and website, often because of discounts applied only on site.
- Thin business information: no clear contact details, returns policy, delivery costs or terms. Google may treat this as misrepresentation. UK shops also need clear pre-contract information under consumer law anyway.
- Delivery and returns settings in Merchant Center that do not match the site.
- Products covered by restricted policies, such as some health products, weapons or counterfeit goods.
- Structured data on product pages showing a different price or availability from the feed.
After a suspension you can request a review once the issue is fixed, but prevention is far cheaper. If you are building a new shop, we include this in ecommerce website design.
How we work as your Google Shopping agency
A Shopping specialist spends as much time in the feed, the tracking and the product pages as in Google Ads itself. Kaptein Beacon is a founder-led studio based in the Netherlands, working remotely with UK retailers and a limited number of clients at a time.
- Strategy session. A 50-minute introductory conversation with the founder about your range, margins, ambition and whether we fit. It costs £225 excluding VAT and is a conversation, not an audit or report.
- Analysis. If we take on the project: Merchant Center, feed quality, structure, search terms, tracking and the share of brand traffic.
- Foundation. Order-level tracking with values, consent in order, an improved feed and margin labels added.
- Structure and targets. Campaigns by margin band and a ROAS target derived from your numbers.
- Ongoing management. Search terms, feed rules, seasons, tests and a monthly report in revenue, margin and cost.
What to look for in any Shopping specialist
- Asks about your margins before your revenue target.
- Keeps Merchant Center and Google Ads in your name.
- Can explain how brand traffic sits inside the results.
- Does not promise a fixed ROAS. Nobody can honestly do that without knowing your data.
Shopping and organic search reinforce each other, because the same product data and category structure serve both; see ecommerce SEO. How click prices are set, and how to size a media budget, is explained in Google Ads cost.