Do you have any of these questions: “What is a Facebook Lookalike Audience?” and “When should I use it?” or “How do I create the best ones?”

Well never fear, I’ll answer all these questions and more and clear up some of the mystery and myths that surround Lookalike Audiences.
What is a Facebook Lookalike Audience?
A lookalike audience takes a seed audience and then goes out and finds a group of other people who are similar to that seed audience. You know that Facebook tracks everything we do (yes it’s creepy but it’s good for marketers) so they know who are the types of people that buy things, click on ads, watch videos, and more.

So, if, for example, you have an email list of customers, you can tell Facebook, “Go out and find 2 million people who are like this list of customers.” Or “Go out and find 2 million people who are like the people who visit my website or hang out there for a long time, or who are like the people who watch these videos on Facebook.

Important things to know about Lookalike Audiences
Lookalike Audiences can only be created from “assets” you own. You can’t create a Lookalike Audience based on a keyword or based on an “Interest” on Facebook.

You can only create Lookalike Audiences from the Custom Audiences that you can create in the Facebook Ads Manager.

Lookalike Audience size will be different for different countries and is based on the population of that country. So a typical size for the US is 2.1 million people at the 1% level. But other countries with smaller populations will be smaller.

Here are some other great tips about Lookalike Audiences from Facebook:

Your Lookalike Audience will only include people from the country/countries you select during creation.
Your source audience must contain at least 100 people from a single country in order for us to use it as the basis for a Lookalike Audience. (I actually prefer to have at least 200 people to allow for better targeting and matching)
You can create up to 500 Lookalike Audiences from a single source audience.
People in your source audience will be excluded from your Lookalike Audience unless you use a pixel as your source audience.
One other tip that Facebook gives you is that you “can” use multiple Lookalike Audiences in your targeting at the same time but I don’t recommend that so that you can test the audiences separately and know which one works best for you.
Another question people have about Lookalike Audiences is “What is a 1% Lookalike Audience vs a 2% Lookalike Audience”. The percentage refers to how closely Facebook will match your audience. 1% means the audience is much closer to the “seed” audience.

Typically I recommend just using 1% audiences to start but if you live in a smaller country or you need to scale your Facebook ads wider, then you may want to test 2%. You can go as high as 10% Lookalikes.

When are they useful?
Lookalike audiences are a very powerful tool when you may not be able to use the right keywords or the right targeting. Lookalike audiences can perform really, really well especially with a good “seed” audience.

Even if you do have good keywords or targeting, make sure you test a Lookalike Audience or two against your other audiences so that you give Facebook a chance to find better conversions for you. The more you split test your ads, the better your results will be.

How you create a Lookalike Audience on Facebook


First go to the Audiences area in your Facebook Ads manager by clicking on the Menu area in the upper left corner (typically 9 dots or 3 lines).
You must first create a Custom Audience (Website visitors, Customer List, Facebook Page Engagement, Instagram Engagement, Video Views, etc). If you have not done that, click the Create Audience, then select Custom Audience and create whichever type of Custom Audience you want to create.
Then create the Lookalike Audience by selecting the blue Create Audience button and select Lookalike Audience.
In the popup box, click into the first box that says “Select an existing audience or data source” and a dropdown menu will appear.
Select the “Other Sources” to get to the Custom Audiences you have recently created and select the one you want from the list. Value-Based sources are only from Pixel data or customer lists that have purchase values.
Select the Country (if applicable – some accounts have you choose the country in the targeting area)
Select the Audience Size (I focus mostly on 1% as mentioned)
Click Create Audience. The audience will then be named with the size, country and name of the original Custom Audience.

How do you know which Lookalike Audiences to create?
Here are some of the seed audiences I like to use for Lookalikes in a general list of most potential (some may be better potential for you):

Customers who have spent the most with you (high Customer Lifetime Value – CLV)
Customers who have purchased multiple times
All customers
Purchase pixel – 180 Days, 90 Days, 30 Days etc (depends on how much purchase data you get)
Add to Cart pixel – 180 Days, 90 Days, 30 Days etc (depends on how much purchase data you get)
Engaged Email Subscribers
All Email Subscribers
Lead pixel – 180 Days, 90 Days, 30 Days etc (depends on how much lead data you get)
Time on Site Visitors
Website visitors for certain pages (if you have enough data)
All website visitors
Video Viewers
People who have engaged with your Facebook Page or Instagram account
If you do have purchase data with your pixel or your list then definitely create a Value Based source Lookalike Audience.

You don’t have to create all of these audiences but they will definitely give you something to test if you run out of good audiences.

Lookalike Audiences can work especially well if you are using Lead Generation or Conversion ads so that Facebook can really learn the types of people that optin or buy.
Source https://medianorms.com/what-is-a-facebook-lookalike-audience/