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Facebook Pixel vs Google Analytics Conversions [Explained]

Tracking Facebook Pixel vs Google Analytics conversions is key to measuring the success of your Facebook campaigns.

KPIs such as Reach, CTR or Engaged Users are directional.

On their own, they are vanity metrics but coupled with attribution insights we can understand and optimize towards key conversion.

As with everything digital, there are nuances to look out for.

In this post, I will explore the difference between Facebook and Google Analytics tracking and attribution, why these metrics will never match, and why it is essential to look at both platforms when measuring the success of your Facebook campaigns.

Note:¬†We also created a simple infographic breaking down the key differences for the more visually inclined ūüôā

Facebook Pixel Conversions

To track Facebook Conversions, you need to have the Facebook Pixel installed on your site along with standard or custom events set up.

Once the events are in place, you can use standard events to optimize your conversion campaigns.

In addition, you can measure results in your ads manager reporting as well as in your Facebook Pixel analytics.

Note: For Facebook to optimize your conversion campaigns leveraging custom events you need to create custom conversions off of custom events.

In the top left menu of the Ads Manager go to Custom Conversions.

Facebook Pixel Custom Conversions


Then create a new custom conversion off of the custom event:

Create a custom conversion off of a custom event

Facebook Pixel Conversion Attribution

Attribution Window

Facebook uses a last-touch attribution model.

Meaning that the last click or view of an ad before a conversion, within the defined attribution window, will be attributed to the conversion.

By default, your conversion window is set to 28 days post click and one-day post view.

Although you can set post click and post view from a 1-day, 7-day or a 28-day window.

To clarify the last ad a user sees or clicks on before converting, regardless of getting to the site from other sources,  will get attributed to that conversion.

As long as the conversion occurs within the specified attribution window.

You can set the default attribution window in the ad account level under the ad account settings:

Setting the Facebook Pixel vs Google Analytics Ad Account Attribution Window

Reporting System Attribution vs Delivery System Attribution

Attribution for the reporting window is defined on the ad account level.

This shows what ads drove conversions in your ad manager reports based on the specified ad account attribution window. (default 1-day post view 28-day post click)

You define attribution for the Delivery System (default 7-day post click 1-day post view) on the ad set level.

Facebook uses the Delivery System attribution window to optimize conversion campaigns.

The collected data determines what ads to show users that will most likely convert within the Ad Sets specified attribution window.

You can define delivery attribution at the bottom of the ad sets edit panel:

Facebook Delivery Attribution Window on the Ad Set Level


Note: Keep in mind that Facebook needs 50 conversions in a 7-day window, per ad set, to run optimally.

If your primary conversion is not generating enough conversions in this time frame, you can substitute your primary conversion with soft conversions such as an engaged user or add to cart.

Google Analytics Conversions (Goals & Ecommerce)

Google Analytics typically tracks Conversions such as goals for leads or soft conversions or e-commerce for product sales.

GA as a reporting platform provides a wealth of on-site user behavior and insights as to how users navigate the site and walk through the funnel before converting.

Google Analytics Conversion Attribution

Google uses a  last-touch attribution model assigning conversions to the most recent source from which the user came.

However, we can still access attribution insights.

These help us understand how the user converts once they reach the website.

To get holistic insights you can access the following reports under Multi-Channel Funnels:

Assisted Conversions
Top Conversion Paths
Time Lag
Path Length

In the model comparison tool, you can look at last interaction (default) first interaction, time decay or create custom models.

This data can be very insightful in getting a better understanding of a user’s multi-channel path to purchase.

Although I look at this information as directional given the limitations of cookie-based tracking. (See below)

People Based Tracking vs Cookie-based tracking (Facebook Pixel vs Google Analytics)

Understanding the difference between people based tracking vs cookie-based tracking is essential.

The Facebook Pixel can track people across devices and browsers as long as they are logged into Facebook or, with Advanced Matching it can identify users if they are logged in or not.

As a result, Facebook can tell you with deterministic data if a user clicks on a mobile ad but converts later on a desktop.

Google Analytics Conversions, however, are cookie-based and it sees the mobile and desktop visitor as two separate users.

So what if a user reaches the site on mobile from a Facebook ad but later returns via an organic search from desktop?

Google Analytics sees these as two users and the last source ‚Äėorganic‚Äô would be the attributed value to that conversion.


Not understanding the difference between the Facebook pixel vs Google Analytics can quickly come across as if there is a facebook conversion discrepancy.

It is imperative to differentiate Facebook analytics vs google analytics so that you can adequately attribute, creative, audiences and sources driving conversions.

Having the ability to read google analytics vs facebook insights empowers you as a digital marketer to:

Understand Creative & Audience Effectiveness РBy looking at facebook pixel and google analytics conversions you can get granular audience and creative insights across different phases of ad exposure and ad engagement.

This will allow you to optimize and improve results over time and produce better creative and targeting.

Identify First & Last Touch Attribution РKnowing the difference between google analytics and facebook pixel conversion attribution allows you to improve or expand the first and last touch advertising channels.

For example, if users are seeing a Facebook Ad before converting through search you can optimize your Facebook Campaign to support search.

Holistic Facebook Campaign Measurement РUnderstanding google analytics facebook attribution enables you to measure campaigns holistically across a users journey.

As a result, you can maximize last touch channels and drive conversions without scaling back on higher funnel Facebook ads.

How do you measure conversion across the Facebook Pixel vs Google Analytics? What do you do to attribute ad effectiveness across the user journey touchpoints?

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