How much budget do you need to start with Google Ads for ecommerce?

It depends on the industry and margin, but below 1,000-1,500 euros per month it is difficult to collect enough data for Smart Bidding. The initial goal is not perfect ROAS, but building a dataset that can be optimized.

Why are Google Ads campaigns not converting?

The most common causes are an unoptimized product feed, incorrect tracking, a target ROAS that is too high, unqualified traffic, or poor site UX. Often the problem is not the campaign itself, but the ecosystem around it.

What is the difference between new and existing customers in campaigns?

Google Ads can distinguish between new and returning customers. Assigning more value to new customers helps drive growth, while working on existing customers improves profitability. Both strategies should be balanced.

Google Ads for Ecommerce: Strategy, Shopping & PMax .

Performance Marketing & Ecommerce

Google Ads for ecommerce: strategy, Shopping and Performance Max in the AI era

Activating campaigns is not enough: you need to build a structure that captures the right demand, optimizes budget intelligently and produces reliable data for business decisions.
This is the difference between a Google Ads account that spends and one that generates profit.

In short

Google Ads for ecommerce works on three levels: capturing existing demand with Search and Shopping, generating latent demand with Performance Max and Display, and recovering users who have already visited the website with remarketing.
An effective strategy does not choose only one of these levels: it integrates them into a coherent system where each format works on the right part of the funnel, with budget allocated according to potential and conversions tracked reliably.

HT&T Consulting strategic infographic on the Google Ads funnel for ecommerce 2025-2026. It shows three levels: Capture (Search & Shopping), Generation (Performance Max, Demand Gen) and Recovery (Dynamic Remarketing). It includes icons for advanced pillars: Optimized Feed (POAS Bidding), New Customer Objective, Consent Mode v2 and Server-Side Tracking.

Google Ads ecommerce: the numbers

65%

of online purchases start with a Google search

Google / Ipsos, 2025

+28%

average ROAS on optimized Shopping campaigns compared to standard campaigns

Google Internal Data, 2025

3.5×

more conversions from users who have already visited the website compared to new users

WordStream Benchmark Report, 2025

−22%

average CPA with Smart Bidding and server-side tracking compared to client-side tracking

−22% average CPA thanks to data modeling with Consent Mode v2 and server-side tracking compared to standard configurations.

Why does account structure make the difference?

Most ecommerce businesses that analyze their Google Ads accounts find the same problem: campaigns that have been active for years, budget flowing, some conversions, but no clear view of what works, why it works and where improvement is possible.

Account structure is not a technical detail. It is the foundation for every decision: how budget is distributed, how Smart Bidding works, how data is interpreted, how successful campaigns are scaled and how wasted spend is stopped.

For an ecommerce business, the optimal structure is built on three levels: existing demand (Search + Shopping), latent demand (Performance Max, Display, YouTube) and recovery (dynamic remarketing).
Understanding which level to cover with which budget is the most important decision an ecommerce business can make for its campaigns.

“An ecommerce business that invests everything in Performance Max without having optimized Shopping is like building the roof before the foundations. The algorithm works better when it has a solid base to learn from.”

Giulia Cancedda
Head of Paid, HT&T Consulting

Google Shopping: feed, structure and optimization

Shopping campaigns are the core of Google Ads for ecommerce. They capture users who are actively searching for a product, show image, price and store name directly in the SERP, and convert at significantly higher rates than text ads for queries with explicit commercial intent.

But Shopping campaigns only work well if the product feed is high quality.
The feed is the engine: the richer, more accurate and better optimized it is, the more Google can show the right products to the right people at the right time.

Feed optimization: the fields that make the difference

Field	Importance	What to optimize
`title`	Critical	Include brand, model, variant and main keywords. Avoid generic titles such as “Men’s shoe”.
`description`	High	Use the first 160 characters for secondary keywords and the main product benefits.
`google_product_category`	High	Use Google’s taxonomy at the most specific level possible; do not stop at “Apparel”.
`custom_label`	High	Custom labels to segment campaigns by margin, seasonality, bestseller status and stock.
`image_link`	Critical	Images on a white or neutral background, product clearly visible, minimum resolution 800×800px.
`price`	Critical	It must exactly match the price on the product page; discrepancies cause disapprovals.
`availability`	High	Update in real time. Out-of-stock products appearing in campaigns burn budget without converting.
`gtin`	Medium	Required for products with an EAN/UPC code. It improves feed quality and ad ranking.

How to structure Shopping campaigns

The recommended structure for an ecommerce business with a medium-to-large catalog involves segmenting campaigns by margin or commercial priority, not only by product category.

High-priority campaign: bestsellers, high-margin products, current promotions
Medium-priority campaign: standard catalog with good rotation
Low-priority campaign: long tail, seasonal products, new arrivals

This structure allows different budgets to be allocated by commercial priority and gives Google Ads clearer signals about which products should be optimized more aggressively.

Performance Max: opportunities and limits for ecommerce

Performance Max is Google Ads’ most automated campaign format.
It automatically distributes ads across all Google channels (Search, Shopping, YouTube, Display, Gmail, Maps), using AI to optimize toward the conversion goal.

For an ecommerce business, it can be very effective, but only if managed with the right level of awareness.

To explore the evolution of automated campaigns further, you can also read our guide on Google AI Max for Shopping and Travel, where we analyze how artificial intelligence is entering Shopping and Travel campaigns as well.

“Performance Max is not a substitute for strategy, but an amplifier. If the base is weak (poor feed, inaccurate tracking, weak conversion signals), PMax amplifies the problems, not the results.”

Elena Battistini
Performance Marketing Specialist, HT&T Consulting

When Performance Max works well

Product feed optimized and updated in real time
At least 30-50 conversions per month to provide the model with enough data
Reliable tracking, preferably server-side
High-quality creative assets (images, videos, headlines, descriptions)
Clear conversion goals correctly configured in GA4
New Customer Acquisition strategy: configure the specific objective to assign additional economic value to conversions generated by users who have never purchased on the website, allowing AI to prospect aggressively but with control.

The limits of Performance Max

Performance Max offers limited transparency: it is difficult to understand where ads are actually shown, which assets perform best and which queries generate conversions. This makes manual optimization almost impossible.

For most ecommerce businesses, the correct strategy is to use Performance Max alongside standard Shopping campaigns, not as a replacement.
Shopping manages explicit demand with more control; PMax explores new segments and channels where the algorithm can find latent demand.

Search Ads for ecommerce: when and how to use them?

Search campaigns in Google Ads for ecommerce make sense in three specific scenarios: branded queries (users searching for your store or brand name), high-intent category queries (“men’s running shoes offer”) and comparison queries (“price comparison X vs Y”).

Using Search for every product query is not efficient, because Google Shopping already captures that demand with richer ads and generally higher conversion rates.
Search becomes essential when you want precise control over the ad message or when you want to capture informational queries that Shopping cannot cover.

RSA: how to build ads that convert

Search ads in Google Ads use the RSA format, Responsive Search Ads, with up to 15 headlines and 4 descriptions that Google combines dynamically. Asset quality determines ad quality and Quality Score, which directly affects cost per click.

Include the main keyword in at least 3 headlines
Use headlines with different value propositions, such as price, shipping, guarantee and uniqueness
Add at least one headline with an explicit CTA (“Buy now”, “Discover the collection”)
Pin the most important headlines, but do not overdo it: too many pins limit algorithm flexibility
Add all available assets: sitelinks, callouts, structured snippets, images and prices

Do not use broad match without active Smart Bidding and enough budget for machine learning. In small ecommerce accounts, broad match without control burns budget on irrelevant queries.

Demand Gen: creating demand on YouTube and Discover

If Search and Shopping capture users who are already searching, Demand Gen campaigns generate visual interest. Thanks to YouTube Shorts, Gmail and the Discover feed, this format is ideal for ecommerce businesses that rely heavily on product aesthetics or impulse purchases.

This approach is close to the logic of programmatic advertising: using data, signals and contexts to reach the user before they express an explicit demand.

Pro tip: Use Lookalike segments inside Demand Gen to find new users similar to those who have already purchased high-value products from your store.

Remarketing: recovering users who did not buy

Most users who visit an ecommerce website do not purchase on their first visit.
Remarketing is used to recover them by showing relevant ads to users who have already interacted with the website, with messages calibrated according to the funnel stage they are in.

For an ecommerce business, the most effective audiences to build are:

Product viewers: users who viewed a product page but did not add to cart
Cart abandoners: users who added to cart but did not complete checkout
Checkout abandoners: users who started checkout but did not complete payment
Recent buyers: for upsell, cross-sell and loyalty programs
High-value customers: a segment to use as a lookalike source to find similar new users

“Remarketing is not about chasing users, but about being present when they are ready to buy.
Users who abandon the cart often need time, not persuasion.”

Asia Frangioni
Performance Marketing Specialist, HT&T Consulting

Budget, bidding and Smart Bidding

Choosing the bidding strategy is one of the most impactful decisions in a Google Ads account.
Smart Bidding strategies (Target ROAS, Target CPA, Maximize Conversions) use Google AI to optimize bids in real time, but they only work well when conversion data is reliable and sufficient.

Which bidding strategy to choose

Strategy	When to use it	Requirements
Target ROAS	Ecommerce with sufficient volume and a clear revenue objective	Min. 30-50 conversions/month, reliable tracking with value
Target CPA	Ecommerce with stable average order value or lead generation	Min. 30 conversions/month, historical CPA available
Maximize Conversions	Initial phase or campaigns with limited history	Defined budget, conversions tracked correctly
Maximize Conversion Value	Ecommerce with products that have very different margins	Differentiated conversion values by product or category
Manual CPC	Only in the initial testing phase or in very small niches	Active daily management, not scalable

Beyond ROAS: the era of POAS (Profit on Ad Spend)

Focusing only on revenue (ROAS) is no longer enough for a mature ecommerce business. The real frontier is optimizing for gross profit. By integrating margin data into the feed or using profit-based conversions, you can instruct the algorithm to promote not only the products that generate the most revenue, but also those that leave more margin in the company’s accounts.

Margin synchronization: use custom_label to group products into margin tiers (e.g. High, Medium, Low).
Predictive bidding: set differentiated Target ROAS values by profit cluster instead of using one single target for the entire account.

This level of optimization often requires deeper integration between the ecommerce platform, product feed, tracking and margin data. It also connects to the design of advanced ecommerce platforms on Shopify and Magento, where data, UX and performance need to work together.

Tracking and signal quality: the hidden prerequisite

Google’s Smart Bidding optimizes based on the conversion signals it receives.
Inaccurate signals (duplicate conversions, missing events, untracked purchases) lead the algorithm to optimize toward the wrong objective, wasting budget in a systematic and invisible way.

For an ecommerce using Shopping and Performance Max campaigns, tracking quality is directly proportional to optimization quality.
It is not a technical detail, but the most impactful lever on overall ROAS.

Use one single conversion source for each action: either GA4 or the native Google Ads tag, not both
Implement server-side tracking to reduce data loss from ad blockers and privacy-first browsers
Regularly verify that conversion numbers in GA4 match actual orders
Enable enhanced conversions in Google Ads to improve matching for logged-in users
Properly implement Consent Mode v2: without explicit consent signals, Google Ads cannot model lost conversions, significantly reducing Smart Bidding effectiveness in the European market

We covered the full ecommerce tracking setup in GA4 in a dedicated article, including dataLayer, events, conversions and Google Ads integration. It is the technical complement to this strategic guide: read the complete GA4 ecommerce guide.

Common mistakes in Google Ads ecommerce campaigns

After analyzing dozens of ecommerce accounts, these are the most frequent errors and those with the greatest impact on wasted budget.

Mistake 1 – Poorly optimized feed

The feed is the foundation of Shopping and Performance Max campaigns.
Generic titles, empty descriptions, overly broad categories and low-quality images all result in missed impressions and higher costs.

Check the feed diagnostics report in Google Merchant Center monthly.
Silent disapprovals — products rejected without notification — are more common than expected.

Mistake 2 – One single budget for different objectives

Putting Shopping, Performance Max and remarketing under the same shared budget means that more aggressive formats consume the entire budget, starving the more efficient ones.

Mistake 3 – Performance Max without brand exclusion

As mentioned, PMax captures branded traffic, artificially inflating ROAS.
Always create a dedicated branded Search campaign and use exclusion lists to prevent PMax from cannibalizing that traffic.

Mistake 4 – Target ROAS too high during learning phase

Setting an unrealistic target blocks Smart Bidding during the learning phase.
The campaign cannot find enough compatible auctions, does not spend, does not collect data and does not improve.

The result is a campaign that looks active but produces no real outcomes.

Mistake 5 – Changing campaigns too often

Every significant change (budget, bidding, targeting) resets the learning phase.
In accounts that are over-managed, campaigns are almost always in learning mode and never generate stable data for optimization.

The rule: wait at least 2 weeks and 30 conversions before evaluating a campaign and making structural changes.

Not managing campaigns directly? Here’s what to check

If you have an agency or a professional managing your Google Ads campaigns, you do not need to know how to configure every campaign.
But you must know what to ask and what to monitor to understand if the work is done properly.

The questions you should ask every month

What is the ROAS of Shopping vs Performance Max? Are they consistent?
How many conversions are attributed to branded traffic? Is brand excluded from PMax?
Is the feed updated and free of disapprovals?
Are campaigns in learning phase or stable?
Has tracking been verified recently? Do GA4 data match real orders?

Signals that something is wrong

High ROAS but flat orders: likely branded traffic attribution
Budget not spending: Target ROAS too high or campaign stuck in learning
Conversions increasing but revenue flat: wrong events tracked as conversions
Increasing CPC without performance changes: poor feed or declining Quality Score

Without an experienced and truly competent agency, the risk is that campaigns appear to work but silently burn budget.

Do you want an audit of your Google Ads campaigns?

HT&T Consulting is recognized among the top agencies for verified expertise, managed volume and campaign performance.

If you want to understand where you are wasting budget, how to improve ROAS or how to structure campaigns to scale sustainably: Request a Google Ads audit

Checklist: what to verify before launching campaigns

Before considering a Google Ads ecommerce account ready, check these points:

Google Merchant Center feed updated and without disapprovals
Product titles optimized with keywords and variants
Custom labels configured for margin or business priority
High-quality images on neutral background
Branded Search campaign separated from Shopping and PMax
Performance Max with complete creative assets (images, videos, headlines, descriptions)
Brand exclusions applied to Performance Max
Remarketing audiences configured (cart abandoners, product viewers)
Conversion tracking with a single active source per action
Enhanced conversions enabled in Google Ads
GA4 connected to Google Ads with imported conversions
Target ROAS or CPA aligned with historical data, not ideal expectations
Budget distributed by funnel stage, not equally across campaigns
GA4 DebugView verified with at least one test purchase
No campaigns stuck in learning due to frequent changes
“New Customer” objective configured for acquisition vs retention
Video assets uploaded in PMax (avoid auto-generated videos)
Consent Mode v2 active and verified for compliance and data modeling

If even 3–4 of these points are incorrect, campaigns will spend but will not optimize as they should.

And in a context where Google Ads is increasingly integrated with AI Overviews and conversational search, having a well-structured account is also a visibility advantage, as explained in the article Google Ads in the era of conversational search.

Frequently asked questions about Google Ads for ecommerce

Does Google Ads really work for ecommerce?

Yes, but only if structured correctly. Google Ads captures existing demand (Search and Shopping), generates new demand (Performance Max and Demand Gen) and recovers interested users (remarketing). Without an integrated strategy, campaigns spend but do not scale.

Is Performance Max better than Shopping?

It is not an either/or choice. Shopping controls explicit demand, while Performance Max expands reach by capturing latent demand. Effective strategies use both together.

How much budget is needed to start with Google Ads ecommerce?

It depends on the sector and margins, but below €1,000–€1,500 per month it is difficult to gather enough data for Smart Bidding. The initial goal is not perfect ROAS, but building a dataset to optimize.

Which metric matters more: ROAS or CPA?

For ecommerce, ROAS is more relevant because it considers order value. However, advanced decisions should focus on profit (POAS), not just revenue.

Why are my Google Ads campaigns not converting?

Common causes include poor feed optimization, incorrect tracking, overly high Target ROAS, unqualified traffic or weak website UX. Often the issue is not the campaign itself, but the surrounding ecosystem.

Is GA4 required for Google Ads?

It is not mandatory, but highly recommended. GA4 provides a full funnel view and allows conversion import into Google Ads to improve Smart Bidding.

What is the difference between new and returning customers?

Google Ads can distinguish between new and existing customers. Assigning more value to new customers drives growth, while focusing on existing ones improves profitability. Both strategies must be balanced.

Is remarketing still effective in 2026?

Yes, it remains one of the highest-ROAS channels. However, it is limited by privacy and cookies, which is why first-party data and server-side tracking are increasingly important.

How long does it take to see results?

Campaigns need at least 2–4 weeks and a minimum number of conversions to exit the learning phase. Stable results typically appear after 2–3 months of continuous optimization.

Should Google Ads be managed in-house or by an agency?

It depends on internal skills. Today, Google Ads requires expertise in feeds, tracking, AI, data and strategy. In many cases, working with an experienced partner reduces costly mistakes and accelerates results.

Bibliography and useful sources

Google Ads Help – Performance Max

Official documentation on Performance Max campaigns, assets, goals and automation logic.
View source

Google Merchant Center Help

Official guide on product feed management, requirements, diagnostics and data quality for Shopping.
View source

Google Ads Help – Smart Bidding

Deep dive into automated bidding strategies such as Target ROAS, Target CPA and Maximize conversion value.
View source

Google Ads Help – Enhanced Conversions

Documentation on advanced conversions and improving first-party data matching.
View source

Google Analytics Help – GA4 & Google Ads

Guide on connecting GA4 with Google Ads to import conversions and improve measurement.
View source

Google Developers – Consent Mode

Technical documentation on Consent Mode, essential for compliance, consent management and data modeling in Europe.
View source

HT&T Magazine – GA4 ecommerce

Operational guide on ecommerce events, dataLayer, conversions and Google Ads integration.
Read article

HT&T Magazine – Google AI Max

Insight into the evolution of AI-driven campaigns in Shopping and Travel.
Read article