Have you ever noticed that your Google Ads account seems to show different conversion results than what you see in Google Analytics 4 (GA4)? You're not alone - this is an extremely common issue that most advertisers face at some point.
In this post, we'll explain exactly why Google Ads and GA4 conversions numbers don't always match up, and provide best practices for dealing with it.
Google Ads vs GA4: Apples and Oranges
The first thing to understand is that Google Ads and GA4 track data differently by design. Google Ads only sees activity stemming directly from Google ads clicks. But GA4 provides a holistic view of all website conversion activity, including organic, social, email, referral, and other traffic channels.
So if someone clicks a Google ad but converts later via a social media click, GA4 attributes that conversion to social while Google Ads still assigns conversion credit for itself.
Neither Google Ads Nor GA4 Is "Wrong"
It's crucial to recognize neither platform is incorrect in how it compiles conversion data. Google Ads isolates the impact of paid ads only. GA4 shows the full buyer journey spanning multiple channels.
Think of them like different vantage points - Google Ads offers the view from the ads themselves, but GA4 sees the entire landscape leading to conversions.
The Time Lag Between Clicks and Conversions
Another factor creating variance is the time delay between ad clicks and eventual conversions. Google Ads assigns conversion credit to the day someone clicks the ad, even if they don't actually convert until much later. But GA4 records conversions on the specific day they occur.
For example:
Someone clicks a Google ad on Monday
The person comes back and converts via organic search on Saturday
In this scenario:
Google Ads registers 1 conversion for Monday
GA4 registers 1 conversion for Saturday
So even though it's the same user and conversion, the perceived timing causes reporting differences.
Best Practices for Reconciliation
When evaluating performance across Google Ads and GA4, keep these best practices in mind:
Use GA4 as the Single Source of Truth
GA4 provides the most comprehensive, multi-channel view of conversion activity and should be considered the primary benchmark for assessing overall business results.
Google Ads has a more isolated view strictly within paid ads themselves. This makes GA4 better suited as the single source of truth, with Google Ads as a supplemental report on paid channel efficacy.
Set Unique Conversion IDs Per Channel
Using channel-specific conversion IDs in GA4 provides clear attribution and reconciliation between sources. For example, set up a conversion ID only used in Google Ads so it's easily isolated from other channels when reviewing GA4 reports.
Custom Channel Groupings
Create a custom channel grouping for paid search sources like Google Ads. This groups activity by common channels to analyse holistically while still separating from other referral streams.
Weekly Analysis
Compare weekly periods rather than daily to account for conversion lag across sources. This smooths out day-to-day timing inconsistencies.
Focus Google Ads on Optimization
When executing in Google Ads itself, do rely on its reporting to directly optimise elements like keywords, ads, and landing pages. Just supplement with GA4's comprehensive data for complete validation.
The Full Customer Journey Matters Most
At the end of the day, customers buy based on their entire journey spanning many touchpoints over time. While differences between Google Ads and GA4 can certainly be confusing, the priority should be the overall customer experience driving conversions rather than isolated channel views.
Optimise towards fulfilling target audience needs beyond granular attribution debates. Facilitating clear communication, frictionless experiences, and conveyance of value at every step should take precedence over reporting mechanics.