What Is Remarketing and How Does It Work?

Remarketing is online advertising aimed at people who have already visited your website, watched your video or are on your customer list. A Google Ads tag or the Meta pixel records their visit, if they consented, and the platform then reminds them of your offer in search, on YouTube, Facebook or Instagram. It does not bring new people: it helps you win back those who already showed interest.

Summary

• Remarketing and retargeting mean the same thing in practice: ads for people who have already been in touch with you.
• It works through a tag on your website or an uploaded customer list. Google now calls it "your data", Meta "custom audiences".
• For visitors from the EU it needs cookie consent. Google and Meta both require this in their own rules.
• In Google, an audience needs at least 100 active people in 30 days, or the ads will not show.
• Exclude people who have already bought, cap frequency and measure what would have happened without the ads.

What is remarketing?

Remarketing is a way of targeting ads, not a campaign type of its own. Google Ads has renamed it "your data" and describes it as reaching people who have previously interacted with your business as they browse Google or partner websites. According to Google, this lets you reach people on more than 2 million websites and apps. On Facebook and Instagram, Meta uses custom audiences built from your own data or from engagement on its platforms.

Two typical examples:

• Online shop: someone puts a pair of shoes in their basket and leaves. Two days later they see the shoes in an Instagram ad.
• Service business: someone looks at your bathroom renovation price list but sends no enquiry. When they later search for "bathroom renovation", they see your ad again, this time with customer reviews, for example.

Remarketing or retargeting: is there a difference?

Not in practice. Google has historically used the word remarketing, while Meta talks about retargeting for website visitor audiences. You may come across a split where remarketing means email and retargeting means ads, but the platforms do not use it. In this article, both terms mean ads for people who have already been in touch with you. If you are still deciding between Google Ads and Meta, see Google Ads or Facebook and Instagram: Where to Put Your First Ad Budget.

How does remarketing work?

There are three steps: you collect a signal, the signal becomes an audience, and you show that audience an ad.

1. Signal. A Google tag or the Meta pixel runs on your website and records a visit or an action. The other route is a customer list, such as email addresses and phone numbers.

2. Audience. In Google Ads you can build segments from your own data: website visitors, app users, people who interacted with your YouTube channel, a customer list (Customer Match) or people who submitted a lead form in your ad. Meta offers custom audiences from your website, app, product catalogue, customer list, videos, Instagram account, lead forms and Facebook Page.

3. Campaign. You add the audience to a campaign and prepare an ad that picks up where the person left off.

A Meta website audience starts filling only from the moment you create it and is not backfilled. Set up the pixel and basic audiences early, even if you only launch remarketing later.

With a customer list, Meta hashes the data before matching it to profiles and points out that under the GDPR you are the data controller for the list and need a legal basis.

Be careful with campaigns that use optimised targeting, such as Performance Max. Your audience is only a signal there, and ads can reach people outside it. Such a campaign is therefore not pure remarketing.

Does remarketing need cookie consent?

For visitors from the EU, yes. The ePrivacy Directive allows storing information on a user's device, or accessing it, only with their prior consent based on clear and comprehensive information. The only exception is what is strictly necessary to provide a service the user explicitly asked for.

Google. For visitors from the European Economic Area you must collect consent and send Google consent signals to use remarketing. Consent Mode does this, and Google has added the parameters ad_user_data and ad_personalization to it, covering consent to advertising use of data and to personalisation. You can implement it in a basic or advanced version: in the basic version, Google tags do not load until the person interacts with the cookie banner. Google's EU user consent policy also requires you to keep records of consent, explain how to withdraw it and name every party that receives the data.

Meta. The Meta Business Tools Terms state that where the law requires consent, such as in the EU, you must ensure, in a verifiable manner, that consent is given before the pixel stores Meta cookies.

Customer lists. For Customer Match, Google requires your privacy policy to disclose that you share customer data with third parties and that you obtain consent where the law requires it.

How exactly to set up consent depends on your cookie banner and consent management tool. Have your lawyer or data protection officer (DPO) check the wording of the banner and your privacy policy. This article is not legal advice.

When are you not allowed to use remarketing?

Google bars advertisers promoting products in sensitive interest categories, such as health or negative financial status, from using their own audiences, which includes your data segments and Customer Match. It also prohibits targeting an overly narrow audience. Meta flags and blocks audiences that contain references to specific health conditions or financial status. An audience called "visitors to the arthritis treatment page" will not get through.

What types of remarketing are there?

• On websites and apps. Ads for past visitors as they browse websites and apps on the Google Display Network, or on Facebook and Instagram.
• In search. Google shows ads to past visitors when they search again after leaving your site. You can raise your bid for these people, for example for anyone who visited in the last 30 days.
• On YouTube. Ads for people who interacted with your videos or channel. The channel must be linked to Google Ads and the content must not be marked as made for kids. On Facebook and Instagram you can reach people who watched your video, for example for at least 10 seconds.
• Customer lists. Google Customer Match shows ads to signed-in users across Search, the Shopping tab, Gmail, YouTube and Display. There is a catch for smaller accounts: every policy-compliant account can use it for observation and exclusions only, and direct targeting requires 90 days of history and more than USD 50,000 in lifetime spend. On Meta, a new account may need a few weeks before it can create a customer list audience.
• Dynamic remarketing for online shops. The ad shows the exact products a person viewed. Google needs a product feed with an ID, price and image for each item. Meta needs a catalogue and the pixel and recommends including people who viewed a product or added it to their basket and excluding those who bought.

Who is remarketing worth it for, and when is it not?

It pays off when people visit your website regularly and some of them leave without enquiring or buying. It helps most where people take longer to decide: higher-priced goods, business services, renovations, courses.

Audience size is what decides it:

• Google: a segment for the Display Network, Search or YouTube needs at least 100 active visitors or users in the last 30 days. A customer list needs at least 100 members added or updated in the last 540 days.
• Meta: the help centre gives no fixed minimum. It suggests waiting until a website audience has several hundred people and warns that it will be smaller than your visit count: it only counts Meta users and leaves out those who opted out of online behavioural advertising.

On top of that, subtract the people who did not give cookie consent.

It will help you less if your website is new and has few visits, if you work in a sensitive category, or if what you mainly need is new customers. In that case, build traffic through search or ads aimed at new audiences first.

How long should people stay in an audience, and how often should they see your ads?

Duration. In Google, a member can stay on a list for a maximum of 540 days. On Meta, you enter the number of days when creating the audience. Set the duration to match how long your customers take to decide. For low-cost goods, days are enough; for a made-to-measure kitchen, it may be months. Build separate audiences for different stages, for example basket abandoners from the last 7 days and price list visitors from the last 60 days, each with its own ad.

Exclusions. Do not keep advertising the same thing to people who have already bought or enquired. Google lets you exclude your data segments, and for catalogue audiences Meta explicitly recommends excluding people who purchased.

Frequency. A small audience sees your ads often. Google can cap the number of impressions per person in Display and Video campaigns, but not in Demand Gen campaigns. On Display, only viewable impressions count towards the cap, and you can only set it after the campaign has been created. With a small audience, also refresh your creative more often.

How do you measure whether remarketing works?

The basis is conversion measurement in Google Ads and the pixel on Meta. Platform figures on their own overstate remarketing, though, because it reaches people some of whom would have bought anyway.

• Check what the platform takes credit for. Under standard attribution, Meta can count conversions up to 1 day after an ad impression, with no click. It also offers incremental attribution, which aims to count only conversions caused by the ad.
• Work out the cost per enquiry or order, not the cost per click.
• Compare with your own data. How many enquiries and orders you see in your CRM, shop and inbox before and after launch.
• Assess remarketing separately. If it shares a campaign with new audiences, you cannot tell what it brings.

We explain how auction prices form in How much do Google Ads cost.

What are the most common remarketing mistakes?

• Running tags without consent. This goes against Google's and Meta's rules and, for EU visitors, against the prior consent requirement.
• Showing the same ad over and over. People have already seen it. Offer something new: reviews, an answer to an objection, free delivery.
• Not excluding customers. You pay to advertise to people who have already bought.
• One audience for everything. A blog reader and someone with a full basket need different messages.
• Durations that are too long and frequency that is too high. The ads start to annoy.
• Treating Performance Max as remarketing. The audience is only a signal there.
• Trusting platform figures alone. Without comparing against your own data, you cannot tell what remarketing really delivered.

Frequently asked questions

Is remarketing legal?

Remarketing is a common tool, but for EU visitors it relies on cookie consent, and for customer lists on a legal basis for using the data. Google and Meta both require consent in their own rules. Check with your lawyer or DPO whether your set-up is in order.

How many visitors do I need for remarketing?

Google shows ads to a segment with at least 100 active people in the last 30 days. Meta gives no fixed minimum and suggests waiting for several hundred people in the audience. Bear in mind that some visitors will not consent.

How long can I reach website visitors?

In Google, up to 540 days. On Meta, you set the number of days yourself. The sensible duration depends on how long your customers take to decide, not on the platform maximum.

Can I upload customer email addresses to Google Ads or Facebook?

Yes, through Customer Match in Google and a customer list on Meta, as long as you have a legal basis for that use. Google, however, only lets smaller accounts use the list for observation and exclusions; direct targeting requires 90 days of history and more than USD 50,000 in spend.

How much does remarketing cost?

You set the budget, and the price of a click or impression comes from the auction. We have not found average prices for Slovakia in Google's or Meta's help pages. Judge results by cost per enquiry or order.

Want remarketing set up properly, from measurement and consent to the ads themselves? See our Remarketing, Google Ads and Facebook and Instagram ads services or ask for a free marketing diagnostic.