Most ecommerce teams have a Google Merchant Center account, and most of them never really open it. They set up the product feed once, connect it to Google Ads, and move on. That is a shame, because Merchant Center quietly decides which of your products Google can show, and it reports on how those products perform. This guide explains what the account actually is, the attributes that make up your feed, and how to read the performance numbers without guessing.
What Merchant Center is (and what it is not)
Google Merchant Center is where your product data lives so Google can show your products across its surfaces. That product data is called the feed: a structured list of every item you sell, with a row per product and a column per attribute (title, price, availability, and so on). Merchant Center is the feed behind Shopping ads and free product listings. It is not an ad platform itself. You do not set budgets or bids here. You manage the catalogue, and other systems (Google Ads, in particular) spend money against it.
A quick spelling note: Google's UK locale and our own homepage call it "Merchant Centre", but it is the same product. This guide uses the US "Merchant Center" throughout because that is what most people search for.
Think of Merchant Center as the shelf, not the salesperson. It decides what is in stock and how each item is labelled. Google Ads decides how hard to push each item to shoppers.
The feed: offer attributes at a glance
Each product in the feed is an "offer", and each offer is described by attributes. Some are required, some are strongly recommended, and the quality of all of them directly limits how well your products can perform. Accurate titles, correct prices, and honest availability are not housekeeping, they are the difference between getting shown and getting filtered out. Here are the ones you will meet first:
id: a unique identifier for the product, usually your SKU. It must stay stable over time.title: the product name shoppers see. The most important text field, because Google matches it to searches.description: a longer text description of the product.link: the URL of the product page on your site.image_link: the URL of the main product image.price: the selling price, including currency. It must match the price on the landing page.availability: whether the item isin_stock,out_of_stock, or on backorder.brand: the product's brand name.gtin: the global trade item number (the barcode), which helps Google identify the exact product.condition:new,refurbished, orused.google_product_categoryandproduct_type: the product's category. The first uses Google's own taxonomy, the second is your own category label.
If a title says "Blue Shoe" but the page sells a red one, or the price in the feed is stale, Google may disapprove the item or simply stop showing it. Feed quality is the ceiling on performance, so it is worth getting right before you blame the campaign.
The performance report: clicks, impressions, CTR
Merchant Center has a Performance report, and it tracks the same kind of pre-click metrics you might know from Search Console. These describe what Google showed and what shoppers clicked, not what happened on your site afterwards. The three you will use most often are:
- Impressions: the number of times your product listings were shown.
- Clicks: the number of times shoppers clicked through to your site.
- CTR (click-through rate): CTR = clicks ÷ impressions. A product with 50 clicks from 1,000 impressions has a 5% CTR.
The useful part is the breakdown. You can read these metrics by product (each offer), by brand, and by category, which tells you which items earn attention and which are shown a lot but rarely clicked. A high-impression, low-CTR product often points to a weak title, a poor image, or an uncompetitive price. Because these are pre-click metrics, they will not tell you revenue or conversion rate. For that, you connect to the sales side, which is where linking Google Ads and GA4 earns its keep.
Feed quality is the ceiling on performance. A great campaign cannot outrun a wrong price or a vague title.
Free listings versus Shopping ads
The same feed drives two different placements. Free listings appear in the Shopping tab and on some other Google surfaces at no cost to you. They are exactly what they sound like: unpaid exposure for your catalogue. Shopping ads are paid placements, driven by the same feed, but bought and managed through Google Ads. The feed is shared, the cost model is not. This is also why Merchant Center performance can change even when you have not touched your ad budget: free listings have their own visibility.
If you are new to the paid side, our Google Ads reporting for beginners guide covers spend, clicks, and conversions in the same plain-English style.
How the feed powers Shopping and Performance Max
Both Shopping campaigns and Performance Max (PMax) campaigns pull products straight from your Merchant Center feed. A Shopping campaign uses the feed to decide which products are eligible to show for a given search. Performance Max goes further: it draws on the same feed but spreads your products across Search, the Shopping tab, YouTube, Gmail, Display, and Maps, with Google's automation choosing where and when. In both cases, the feed is the source of truth. If a product is missing, disapproved, or marked out of stock, no campaign can promote it. Fixing the feed is often the fastest performance win available, because it unlocks inventory the campaigns were never allowed to touch.
Feed attribute cheat sheet
| Attribute | What it is | Why it matters for performance |
|---|---|---|
id |
Unique product identifier, usually your SKU | Keeps reporting and history stable; changing it resets a product's data |
title |
The product name shoppers see | Google matches it to searches, so a clear title drives impressions and CTR |
price |
Selling price with currency | Must match the landing page or the item is disapproved; price drives clicks |
availability |
In stock, out of stock, or backorder | Out-of-stock items stop showing, so stale values waste eligibility |
image_link |
URL of the main product image | The image is the listing; a poor one tanks CTR even with good ranking |
gtin |
Barcode / global trade item number | Helps Google identify the exact product and match it to demand |
google_product_category |
Category from Google's taxonomy | Improves matching and lets you read performance by category |
In Clearly
In Clearly you connect Merchant Center alongside your other sources, then read product-level performance in one place. You can see clicks, impressions, and CTR broken down by item, brand, and category, which is the same view as the native Performance report but laid out next to the rest of your marketing rather than stranded in its own tab.
The point of having it in one report is comparison. Putting Merchant Center clicks and impressions next to Google Ads spend lets you ask the useful question: are the products getting attention the same ones getting budget? When a high-CTR product is barely funded, or a heavily funded one is being ignored by shoppers, the answer is sitting in a single shared report instead of two browser tabs.
Where to start
Open Merchant Center, check that your top products are approved and in stock, and read the Performance report by product. Sort by impressions to find items Google is showing, then look at their CTR to see which titles and images are working. Fix the obvious feed issues first, because they cap everything downstream, and only then worry about bids and budgets. The feed is the foundation; the campaigns are just how hard you push it.