Google Merchant Centre is one of the most important parts of Google Ads for eCommerce, but it is also one of the most commonly ignored.
A Shopify store owner might look inside Google Ads and think the campaign is the problem. Performance Max is spending. Shopping results are weak. Products are not getting clicks. ROAS is poor. Sales are inconsistent.
But the real issue may not be the campaign.
It may be Google Merchant Centre.
Merchant Centre is where Google reads, reviews and approves your product data before your products can appear across Google Shopping, Performance Max and free product listings.
If Merchant Centre is messy, your Google Ads account starts from a weak position. Your products may be disapproved, limited, underfed, miscategorised, mismatched, or simply not understood properly by Google.
That means your ads can technically be running, but your best products may not be showing properly.
This is where many Shopify and eCommerce stores waste money. They keep adjusting budgets and campaigns without fixing the product data that Google is using in the first place.
If your products are not showing, not converting, or not getting the right visibility, Merchant Centre should be one of the first places you check.
What Google Merchant Centre Actually Does
Google Merchant Centre is the system that holds your product data for Google Shopping and eCommerce advertising.
It tells Google what your products are, how much they cost, whether they are in stock, what images should be shown, what shipping options apply, what category they belong to and whether they meet Google’s requirements.
For a Shopify store, Merchant Centre usually receives product data from a feed. This may come through the Google and YouTube app, Simprosys, another feed app, or a custom feed setup.
That feed includes information such as:
Product title
Product description
Product image
Price
Sale price
Availability
Brand
GTIN or product identifier
Product category
Product type
Variant details
Shipping information
Product URL
Google uses this data to decide whether your products are eligible to show and which searches they may be relevant for.
This is why Merchant Centre is not just a technical admin area.
It directly affects Google Shopping visibility, Performance Max results and paid eCommerce performance.
If the data is weak, Google has less to work with.
If the data is wrong, products can be restricted or disapproved.
If the feed is missing important information, your products may be less competitive.
Why Merchant Centre Problems Hurt Google Ads
Google Ads and Merchant Centre are connected.
Performance Max and Shopping campaigns rely heavily on your Merchant Centre feed. If your feed is poor, your campaigns are working with poor inputs.
This is especially important for Shopify stores running Performance Max because the campaign may use product data across Shopping, Search, Display, YouTube, Discover, Gmail and other placements.
If the product data is unclear or incomplete, Google may struggle to match your products with the right buyers.
Merchant Centre problems can hurt performance in several ways.
Products may stop showing completely.
Products may be approved but limited.
Google may misunderstand what the product is.
Poor titles may reduce Shopping relevance.
Weak images may reduce click-through rate.
Incorrect prices may trigger disapprovals.
Stock mismatches may stop products from showing.
Shipping errors may restrict listings.
Missing identifiers may reduce product quality.
Low-quality feed data may make Performance Max less effective.
This is why reviewing only the Google Ads campaign is not enough.
If your campaign is spending but not producing sales, you need to check whether Merchant Centre is clean, accurate and giving Google the right product information.
Product Disapprovals Are the Obvious Problem
Product disapprovals are the most visible Merchant Centre issue.
A disapproved product usually cannot show in Shopping ads or free listings until the issue is fixed.
That sounds simple, but many stores let disapprovals sit for weeks or months because nobody is checking Merchant Centre properly.
Common reasons for product disapprovals include:
Incorrect price
Incorrect availability
Missing required product data
Image problems
Policy issues
Broken product URLs
Mismatched product information
Missing shipping settings
Restricted products
Website crawl problems
A disapproval is not always complicated, but it can still cost money.
If a best-selling product is disapproved, you may lose visibility on one of your most valuable items. If a large number of products are disapproved, Performance Max may be left with only part of your catalogue to work with.
The dangerous part is that Google Ads may still be spending. The campaign does not always make it obvious that important products are missing from the feed.
That is why Merchant Centre should be checked regularly, not just when something breaks.
Price Mismatches Can Stop Products Showing
One of the most common Merchant Centre problems is a price mismatch.
This happens when the price in your product feed does not match the price on your Shopify product page.
For example, your Shopify store may show a product for $129, but the feed sends $139 to Merchant Centre. Or your product page may show a sale price, but Merchant Centre still sees the original price. Or a variant may have a different price from the parent product, and Google picks up the wrong value.
Google does not like inconsistent pricing because it creates a poor shopper experience.
If the price shown in Google Shopping does not match the website, the product may be disapproved or limited.
Price mismatches can happen because of:
Delayed feed updates
Sale prices not syncing correctly
Variant pricing issues
Currency problems
Caching issues
App conflicts
Manual feed edits
Incorrect structured data on the product page
For Shopify stores, this is especially common during sales, promotions and bulk price changes.
If you run a sale but your feed does not update cleanly, products may become restricted right when you need them visible most.
Before launching a major promotion, it is worth checking that sale pricing is being passed correctly to Merchant Centre.
Availability Mismatches Are Just as Damaging
Availability mismatches happen when Google sees different stock information in your feed compared with your Shopify site.
For example, your feed might tell Google that a product is in stock, but the product page says it is sold out. Or Shopify may show the product as available, but Merchant Centre receives out-of-stock data.
Either way, this can cause products to stop showing or become limited.
Availability problems often come from:
Poor feed syncing
Variant stock issues
Backorder settings
Preorder products
Multiple inventory locations
Product app conflicts
Theme or structured data issues
Manual product edits
Delayed updates between Shopify and Merchant Centre
This matters because Google wants product information to be accurate.
If shoppers click an ad and land on an out-of-stock product, that creates a bad experience. Google may restrict the product as a result.
For eCommerce stores with fast-moving stock, this is a serious issue.
If your best products regularly move in and out of stock, your feed needs to update reliably. Otherwise, Google Ads may waste budget or lose visibility on products that should be performing.
Shipping Settings Can Create Hidden Problems
Shipping is one of the most frustrating areas inside Google Merchant Centre.
Many Shopify store owners assume shipping is handled by Shopify, so there is nothing else to worry about.
That is not always true.
Google also needs to understand your shipping settings inside Merchant Centre. If the shipping information in Merchant Centre does not match what customers see on your website, products can be restricted.
Common shipping issues include:
Missing shipping rates
Incorrect shipping country
Free shipping shown in one place but not another
Shipping cost mismatch between Merchant Centre and checkout
No delivery timeframe
Incorrect minimum order threshold
Different shipping rules for different products
Bulky items with special shipping conditions
Regional exclusions not set correctly
This is a big issue for Australian eCommerce stores because shipping can vary by metro, regional and remote areas.
If your product page says “free shipping” but checkout adds a fee, that is not just a conversion problem. It can also create trust and compliance issues.
Google wants the shopper to receive accurate information before they click.
If your shipping setup is unclear, Merchant Centre may limit visibility. Even if it does not, customers may abandon checkout when the real shipping cost appears.
Shipping is not just an operations issue. It affects Google Shopping performance and conversion rate.
Weak Product Titles Reduce Shopping Visibility
Product titles are one of the most important parts of a Google Shopping feed.
They help Google understand what the product is and when it should appear.
Many Shopify stores use product titles that look fine on the website but are too vague for Shopping.
For example:
“Classic Tee”
“Luna Dress”
“Signature Candle”
“Premium Grinder”
“Travel Pack”
These titles may suit a brand website, but they do not give Google enough useful information.
A stronger Shopping title usually includes more detail:
Brand
Product type
Gender or audience
Colour
Size
Material
Key feature
Use case
Model or variant
For example, instead of:
“Signature Candle”
A better feed title might be:
“Aurevia Signature Soy Candle 250g Golden Hour Amber”
That gives Google far more context.
The goal is not keyword stuffing. The goal is clarity.
If your product titles are weak, Shopping relevance can suffer. You may miss searches that should be a good fit, or Google may match your products to less useful traffic.
For Shopify stores, improving product titles can be one of the simplest ways to improve feed quality.
Missing Product Identifiers Can Limit Performance
Google often wants product identifiers such as GTINs, MPNs and brand names.
A GTIN is usually the barcode or global trade item number for the product.
If you sell branded products, missing identifiers can reduce Google’s ability to understand and compare your items.
This can affect Shopping performance because Google uses identifiers to match products with known items in its catalogue.
Missing identifiers may not always cause a full disapproval, but they can reduce feed quality or limit performance.
This is common for stores that sell:
Coffee machines
Appliances
Electronics
Beauty products
Homewares
Branded fashion
Health products
Accessories
If you sell custom, handmade or private-label products, you may not have GTINs. That can be fine, but the feed still needs to be set correctly so Google understands that the product does not require one.
Problems happen when products are marked incorrectly.
For example, a product that has a GTIN is submitted without one. Or a custom product is treated as if an identifier exists when it does not.
These details sound small, but they affect feed health.
Product Images Can Trigger Issues or Reduce Clicks
Product images matter in Google Shopping.
They affect both approval and performance.
Google has image requirements, and poor images can cause restrictions. But even when images are approved, they may still perform badly if they do not make the product clear.
Common image problems include:
Text overlays
Watermarks
Promotional badges
Low-resolution images
Lifestyle images used when a clean product image is needed
Incorrect variant images
Poor cropping
Images not matching the product
Placeholder images
Broken image URLs
For Shopping ads, the image is often the first thing people notice.
If your competitor’s product image is cleaner, brighter and easier to understand, they may win the click even if your product is better.
For Shopify stores, image issues often happen at variant level. A customer searches for a black product, but the image shows a different colour. Or the feed sends the parent product image instead of the selected variant.
That creates confusion and can reduce conversion rate.
Your product images should be accurate, clear and consistent across Shopify, Merchant Centre and Google Shopping.
Approved Products Can Still Perform Poorly
A product being approved does not mean it is well optimised.
This is an important point.
Many store owners check Merchant Centre, see that products are approved and assume everything is fine.
But approval is only the minimum requirement.
A product can be approved and still have poor feed quality, weak titles, missing attributes, bad images, low relevance or poor competitiveness.
Approved does not mean strong.
It simply means the product is allowed to show.
For better Shopping and Performance Max results, you need to look beyond approval status.
Ask:
Are the titles strong enough?
Are the product categories accurate?
Are descriptions useful?
Are images competitive?
Are variants handled properly?
Are best sellers easy to identify?
Are low-margin products being controlled?
Are product types structured clearly?
Are custom labels being used properly?
Are shipping and pricing accurate?
This is where feed optimisation matters.
Fixing disapprovals is step one.
Improving product data is where the real performance gains often come from.
Shopify Feed Apps Can Help or Create More Mess
Most Shopify stores use an app to send product data to Google Merchant Centre.
Common options include the Google and YouTube app, Simprosys and other feed management tools.
These apps can be useful, but they are not magic.
If they are configured badly, they can send poor data, duplicate products, incorrect variants, wrong categories or inconsistent information.
Problems can include:
Duplicate feeds
Multiple apps sending product data at the same time
Incorrect product categories
Variant URLs not handled properly
Sale prices not syncing
Shipping data not passing correctly
Custom labels not set up
Feed rules conflicting with app settings
Products excluded by mistake
Old feeds still active in Merchant Centre
Duplicate feeds are especially dangerous.
If Merchant Centre is receiving product data from multiple sources, it can become messy quickly. You may not know which feed is controlling which product. Fixing one source may not fix the actual issue if another feed is overriding it.
For Shopify stores, feed setup should be kept as clean as possible.
One reliable source of truth is better than several apps fighting each other.
Product Categories Help Google Understand Your Catalogue
Google product categories help Google classify your products.
In many cases, Google can automatically assign categories, but that does not mean you should ignore them.
For some products, especially in competitive categories, better categorisation can help Google understand what you sell and where your products fit.
Shopify product types and Google product categories are not the same thing.
Your Shopify product type might be:
“Accessories”
But Google may need a more specific category, such as a bag, jewellery item, home decor piece or kitchen appliance.
The more accurately your products are classified, the easier it is for Google to understand them.
This is not about gaming the system. It is about removing confusion.
If you sell a wide catalogue, product types, collections, categories and feed labels should be organised properly.
A messy catalogue creates messy advertising.
Product Feed Optimisation Supports Performance Max
Performance Max relies heavily on your product feed for eCommerce campaigns.
This means Merchant Centre problems do not stay isolated inside Merchant Centre. They flow into your campaign performance.
If your feed is poor, Performance Max has weaker information.
If your product titles are vague, matching can be weaker.
If your best products are disapproved, the campaign cannot push them.
If your low-margin products are included with no structure, budget can drift.
If your images are poor, click-through rate can suffer.
If your shipping is unclear, conversion rate can fall.
Performance Max is automated, but it cannot fully overcome bad product data.
Better feed data gives the campaign a better chance.
This is why a proper Performance Max review should always include Merchant Centre and product feed analysis.
Looking only inside Google Ads is not enough.
Not Every Product Should Be Treated Equally
One of the biggest feed strategy mistakes is pushing every product with the same priority.
Not all products deserve the same visibility.
Some products have strong margins. Some are best sellers. Some are seasonal. Some are low-margin fillers. Some are often out of stock. Some convert well organically but perform poorly in paid traffic. Some are good for repeat purchases. Some are useful add-ons but weak first-purchase products.
Merchant Centre and your product feed should help you organise this.
Custom labels can be used to group products by:
Best sellers
High margin
Low margin
Sale items
Seasonal products
New arrivals
Clearance stock
Price range
Stock level
Priority products
This gives you more control when reviewing performance and structuring campaigns.
Without labels or a clear product strategy, Performance Max may spend on products that do not make sense commercially.
Google may find clicks, but that does not mean the clicks are profitable.
Feed strategy should be connected to business strategy.
Why Products May Not Show Even When They Are Approved
This is a common question.
A Shopify store owner checks Merchant Centre and sees products approved, but they still do not appear in Shopping results.
There are several possible reasons.
The product may have low search demand.
The bid strategy may not be competitive.
The product title may be too weak.
The product may be outranked by competitors.
The campaign budget may be limited.
The product may be eligible but rarely selected by Google.
The landing page may have low quality signals.
The price may be uncompetitive.
The product may be limited in certain placements.
The feed may lack important attributes.
Approval is not a guarantee of visibility.
It only means the product is allowed to appear.
To actually show and compete, the product needs relevance, commercial strength, good feed data and enough campaign support.
This is why Merchant Centre reviews need to go beyond fixing red warning icons.
You need to understand which products are eligible, which products are being shown, which products are getting clicks and which products are producing sales.
A Simple Merchant Centre Checklist for Shopify Stores
If you are running Google Shopping or Performance Max, check these basics.
Are all key products approved?
Are any products disapproved or limited?
Do prices match Shopify?
Does stock availability match Shopify?
Are sale prices syncing correctly?
Are shipping settings accurate?
Do product images meet Google’s requirements?
Are product titles clear and descriptive?
Are product descriptions useful?
Are GTINs or identifiers included where needed?
Are custom products marked correctly?
Are Google product categories accurate?
Are variants handled properly?
Is only one main feed source being used?
Are duplicate feeds causing confusion?
Are best sellers easy to identify?
Are low-margin products controlled?
Are products grouped with useful labels?
Are Merchant Centre warnings being reviewed regularly?
This checklist will not solve every issue, but it will quickly show whether your feed is helping or hurting performance.
When to Get Help With Google Merchant Centre
Some Merchant Centre issues are simple. You can fix a missing shipping setting, update a product title or resolve a basic disapproval yourself.
But if your store is spending serious money on Google Ads, Merchant Centre should not be treated casually.
It may be worth getting help if:
Products are being disapproved repeatedly.
Shopping ads are not showing properly.
Performance Max is spending but not converting.
Shopify stock and Merchant Centre stock do not match.
Sale prices are not syncing properly.
Shipping warnings keep appearing.
You have multiple feeds and do not know which one is active.
Your product titles and categories are weak.
Your best products are not getting visibility.
You do not trust the data inside Merchant Centre.
You are preparing to scale Google Ads spend.
The danger is not just that products stop showing.
The bigger danger is that you keep making campaign decisions without realising the product data underneath is broken.
You might increase budget on a campaign that is missing your best sellers. You might blame Performance Max when Merchant Centre is the real issue. You might pause products that could perform well with better feed data. You might waste money sending traffic to products with pricing, shipping or availability problems.
That is why Merchant Centre needs to be part of any serious Google Ads review for Shopify and eCommerce stores.
Final Thought
Google Merchant Centre is not just a technical setup tool.
It is one of the foundations of eCommerce advertising on Google.
If your product data is clean, accurate and well structured, Google has a much better chance of showing your products to the right shoppers.
If your Merchant Centre setup is messy, your campaigns may struggle before they even get a fair chance.
Product disapprovals, price mismatches, availability issues, shipping errors, weak titles, missing identifiers, poor images and duplicate feeds can all hurt performance.
The frustrating part is that many of these problems sit quietly in the background while your Google Ads budget keeps spending.
Before increasing your budget, changing your campaign structure or blaming Performance Max, check Merchant Centre properly.
Your products need to be eligible, accurate, competitive and clearly understood by Google.
That is where better Shopping and Performance Max performance often starts.
If your products are being disapproved, limited or not showing properly in Google Shopping, I can help you find out why. I review Google Merchant Centre, Shopify product feeds, product data, shipping settings and Performance Max campaigns to identify what is stopping your products from getting the right visibility.
If you’re running Google Ads and you’re not confident your budget is working as hard as it should, I offer a free, no-obligation Google Ads audit for Sydney businesses. I’ll personally review your account, identify exactly where money is being wasted, and show you a clear path to better results.
Book your free Google Ads audit today. Contact Phil Adair at Yes Online Marketing – Sydney’s Google Ads specialist with 17+ years experience. Call 0410 445 717 or visit yesonlinemarketing.com
There’s no cost and no obligation – just an honest assessment of what’s working, what isn’t, and how to fix it fast.