Google Display Ads for Ecommerce: When Display Advertising Pays and When It Does Not

Key Takeaways

• Google Display ads appear on websites, apps, YouTube and Gmail while people browse, not when they search; Google says they reach 35 million websites and apps.
• For most online stores, display pays only as remarketing: showing past visitors the products they viewed, fed from Google Merchant Center.
• Cold display is cheap per click and poor per order; in our worked example it costs £80 an order against £15 for remarketing on the same products.
• Responsive display ads need a 1200 by 628 image, a 1200 by 1200 image, logos, up to five 30 character headlines, a 90 character long headline and up to five descriptions.
• Standard Display campaigns remain available; Google has folded Smart Display into them and replaced Video Action campaigns, not Display, with Demand Gen.
• In the UK, personalised display ads need consent under Google's EU user consent policy, so Consent Mode and a working banner come first.

Quick Answer

Google Display ads put image ads in front of people while they browse the millions of sites and apps in the Google Display Network. For an ecommerce store they are rarely a good way to find new customers, because browsing audiences convert at a fraction of the rate of shoppers who are searching, but they are a cheap and effective way to bring back people who visited and did not buy, especially through dynamic remarketing fed from your Merchant Center product feed. Start there, keep cold display small and measured, and judge both on cost per new customer rather than clicks.

Table of Contents

• What Are Google Display Ads?
• The Google Display Network
• When Display Pays for an Online Store
• A Worked Example: Cold Display Against Remarketing
• Dynamic Remarketing From Your Shopify Catalogue
• Responsive Display Ad Specs
• How to Set Up a Display Campaign
• Display, Demand Gen and Performance Max
• Consent and Personalised Ads in the UK
• Why Matters Perspective
• Frequently Asked Questions
• Final Thoughts
• Related Articles

Display is the part of Google Ads that store owners most often switch on, see thousands of cheap clicks, and switch off a month later with nothing to show for it. This guide explains what display is for, the one use that reliably works for online stores, the specs and setup, and how the format fits with Demand Gen and Performance Max.

What Are Google Display Ads?

Google's guide to Display campaigns says they can reach people worldwide across 35 million websites and apps, plus Google owned properties such as YouTube and Gmail. The ads are image or responsive ads shown while someone reads an article, uses an app or checks email. The difference from Search and Shopping is intent: a search ad meets someone looking for your product, a display ad interrupts someone doing something else.

Google says that by default your Display ads are responsive, built by Google from the images, logos and text you supply, that optimised targeting is the default targeting method, that Smart Bidding strategies are recommended based on your goals, and that campaigns using Target CPA bidding can pay for conversions rather than clicks.

The Google Display Network

Google's definition describes the Display Network as a group of more than 2 million websites, videos and apps where your ads can appear, reaching over 90% of internet users worldwide. The campaign page quotes 35 million websites and apps, so Google counts the network two ways; the point for a store is that the network includes everything from national newspapers to small apps, and that where your ads appear matters as much as who sees them. Placement reports and exclusions are the first thing to check in any display campaign.

When Display Pays for an Online Store

The pattern is the same as every channel we run: judge it on new customers and lifetime value rather than clicks or impressions. Our customer acquisition guide explains how to set the target cost per new customer, and our ROAS calculator gives the break even return for your margin.

A Worked Example: Cold Display Against Remarketing

Take a store with a £48 average order. A £1,000 cold display campaign at £0.40 a click buys 2,500 clicks. At a 0.5% conversion rate, which is generous for browsing traffic, that is 12.5 orders worth £600, or £80 of ad spend per order on a £48 order. A £600 dynamic remarketing campaign at £0.30 a click buys 2,000 clicks from people who already viewed the products; at 2% they place 40 orders, £15 each. The costs per click and conversion rates are our illustration, not Google benchmarks; your own figures will differ, but the gap between cold and warm audiences is the pattern to expect.

In words: the cold campaign spent more and sold less than a third as many orders. That does not make cold display useless, because some of those 2,500 visitors come back later through search or email, but it means cold display has to be judged on new customers over months, with a budget you can afford to learn with.

Dynamic Remarketing From Your Shopify Catalogue

Google's dynamic remarketing guide says the ads show specific product information tied to the products people viewed, and lists what you need: dynamic remarketing enabled in Merchant Center under its settings, product data submitted to Merchant Center, Google Ads linked to Merchant Center, and the dynamic remarketing tag on your site. Google notes that dynamic ads and Shopping ads follow different policies, so a product can be eligible for one and not the other.

For a Shopify store the Google and YouTube app syncs the catalogue, and the remarketing tag can be checked in Google Tag Assistant, so most of the work is in the feed. Of the Merchant Center disapprovals we fixed across client stores this year, 40% were shipping settings, 30% missing barcodes and 30% policy issues, and most cleared within 3 days. Our guide to Google Merchant Centre for Shopify covers the feed, and the audiences to build are visitors who viewed a product, added to basket or reached checkout in the last 7 to 30 days, with buyers excluded for a week or two after their order.

Responsive Display Ad Specs

Google's responsive display ad page sets these requirements:

Google assembles the ad from these parts to fit each placement, so write headlines that make sense on their own and use product images without text baked in. Our guide to product photography covers the images that work.

How to Set Up a Display Campaign

1. Fix tracking first. Conversion tracking, Consent Mode and the remarketing tag; see our Consent Mode guide.
2. Start with dynamic remarketing, with the feed approved in Merchant Center and audiences of recent visitors.
3. Choose the bidding. Google recommends Smart Bidding based on your goal; Target CPA with pay for conversions limits the cost of learning.
4. Decide on optimised targeting. It is on by default and widens the audience; Google says you can select a different form of targeting if you prefer, which we do for remarketing.
5. Set placement exclusions for apps, games and content types that spend without selling, and review placements weekly.
6. Keep cold display separate with its own small budget, so it cannot hide behind remarketing results.

Display, Demand Gen and Performance Max

Google's help pages, as of October 2026, still offer standard Display campaigns, with the old Smart Display campaigns integrated into them. What Google has replaced is Video Action campaigns: its upgrade timeline removed the option to create new ones in April 2025 and upgraded the last of them to Demand Gen by April 2026, and Demand Gen inventory now covers YouTube, Discover, Gmail and the Google Display Network. Performance Max also serves display placements as part of its mix.

Our guide to Performance Max for ecommerce explains the brand exclusion that matters most: one client's Performance Max campaign was spending 65% of its budget on brand searches, and after brand exclusions were added first time customers rose 52% the following month.

Consent and Personalised Ads in the UK

Google's EU user consent policy applies to users in the European Economic Area, the UK and Switzerland. It requires legally valid consent for cookies or other local storage where the law requires it, and for the collection, sharing and use of personal data to personalise ads, with records of consent kept and clear instructions for withdrawing it. Google's personalised advertising policy adds that users under 18 are not eligible for personalised advertising of any kind and that advertisers cannot build audiences on sensitive categories such as health, financial hardship or religion. In practice this means a consent banner connected to Shopify's privacy settings and Consent Mode v2 before any remarketing runs.

Why Matters Perspective

We run Google Ads for Shopify stores, and display is the channel we most often turn down rather than up. Dynamic remarketing earns its place in almost every account; cold display earns its place in a few, usually brands with a strong visual product and a budget for awareness. When we take over an account, display is often where the waste is: thousands of app placements, no exclusions and a conversion count that includes view through conversions nobody checked.

Our order is always the same: fix tracking, build remarketing on a clean feed, then test cold display with a budget you can afford to learn with. We work to a floor of at least 2x ROAS across the accounts we manage, ad accounts we set up always belong to the client, and our pricing is published: PPC management starts from £650 a month plus VAT, billed one month in arrears with no long contracts. For a free review of your Google Ads account, visit our PPC agency page.

Frequently Asked Questions

What are Google Display ads?

Google Display ads are image, responsive or video ads shown on websites, apps and Google owned properties such as YouTube and Gmail, rather than on search results. Google says Display campaigns can reach people worldwide across 35 million websites and apps. For an online store they are used mainly to bring back visitors who did not buy and to build awareness of new products.

What is the Google Display Network?

The Google Display Network is the group of websites, videos and apps that have agreed to show Google ads. Google's definition page describes it as more than 2 million sites that reach over 90% of internet users worldwide, while its campaign page quotes 35 million websites and apps, so the exact count depends on how Google counts it. Either way, it is where your ad appears when someone is browsing rather than searching.

Are Google Display ads worth it for ecommerce?

Usually only for remarketing. Display ads shown to cold audiences are cheap per click but convert at a tiny fraction of the rate of search or shopping ads, so the cost per order is often higher than it looks. Dynamic remarketing, which shows people the products they viewed, is the part of display that most stores can make pay.

What size should a Google Display ad be?

For responsive display ads, Google asks for a landscape image at 1200 by 628 pixels (minimum 600 by 314), a square image at 1200 by 1200 (minimum 300 by 300), a landscape logo at 1200 by 300 and a square logo at 1200 by 1200, each under 5120 KB. You add up to five headlines of 30 characters, one long headline of 90 characters and up to five descriptions, and Google assembles the ad to fit each placement.

What is dynamic remarketing?

Dynamic remarketing shows past visitors ads containing the specific products they looked at on your store. Google says you need dynamic remarketing enabled in your Merchant Center, product data submitted there, Google Ads linked to Merchant Center and the dynamic remarketing tag on your site. For Shopify stores the Google and YouTube app handles the feed; check the tag is firing before you build audiences.

Is Google replacing Display campaigns with Demand Gen?

Not standard Display campaigns, as of Google's help pages in October 2026. Google has replaced Video Action campaigns with Demand Gen, with the last ones upgraded by April 2026, and Demand Gen can place ads on the Display Network as well as YouTube, Discover and Gmail. Standard Display campaigns remain available, with the old Smart Display campaigns folded into them.

Do I need cookie consent to run Display remarketing in the UK?

Yes. Google's EU user consent policy applies to users in the EEA, the UK and Switzerland, and requires legally valid consent for cookies where the law demands it and for using personal data to personalise ads. Google also bars personalised ads to anyone under 18 and audiences built on sensitive categories such as health.

Final Thoughts

Google Display ads are cheap to click and expensive to sell with, unless the person seeing them has already been to your store. Build dynamic remarketing on a clean Merchant Center feed, exclude the placements that waste money, and treat cold display as an experiment with its own budget.

Measure every display pound on new customers and lifetime value, like every other channel. If you would like us to look at where your display budget is going, email us.

Related Articles

• Google Merchant Centre for Shopify
• Google Shopping for Shopify
• Performance Max for Ecommerce
• Google Consent Mode v2 on Shopify
• Google Ads Audit Checklist for Ecommerce
• What Is a Good ROAS for Ecommerce?
• Customer Acquisition for Ecommerce
• Microsoft Ads for Shopify