You've been in this meeting before. The client asks how their ads are performing. You pull up Meta — looks solid. You pull up Google Ads — also looks solid. Then the client opens GA4, and suddenly none of the three numbers agree. Conversions are different. Revenue is different. ROAS is all over the place.
Every agency running both Meta and Google Ads deals with this. It's not a bug, and it doesn't mean your tracking is broken. It means each platform is measuring the same customer journey in a fundamentally different way.
The core issue: attribution models
When someone sees a Meta ad on Monday, clicks a Google ad on Wednesday, and buys something on Thursday — who gets credit for the sale?
The answer depends entirely on which platform you're looking at, and which attribution model it's using.
- Meta Ads defaults to a 7-day click and 1-day view attribution window. If someone saw your ad and bought within 7 days — even if they clicked a Google ad in between — Meta claims the conversion.
- Google Ads defaults to data-driven attribution, which distributes credit across multiple touchpoints in the path to purchase. But it still reports conversions in its own dashboard.
- GA4 uses last-click attribution by default unless you've configured it otherwise, meaning whoever drove the final click gets full credit.
The result: a single customer can be counted as a conversion in all three platforms simultaneously. Your total reported conversions can be 2–3x your actual conversions. This is called conversion overlap, and it's the main reason your numbers never match.
View-through conversions inflate Meta numbers
Meta's default attribution includes view-through conversions — conversions that happen within 1 day of someone simply seeing your ad, even if they never clicked it.
This is the most common reason Meta ROAS looks dramatically higher than Google ROAS for the same time period. Meta is claiming credit for purchases that happened organically, through Google search, or through direct traffic. Someone could have searched your brand name on Google, bought directly, and Meta would count that as a conversion if they'd seen your ad in the previous 24 hours.
Quick fix: In Meta Ads Manager, go to Columns → Customize Columns → and add "7-day click" as a separate column alongside your default "7-day click, 1-day view" total. The difference between those two numbers is how many conversions Meta is claiming via view-through. For most accounts it's significant.
Different time zones and attribution windows
Meta and Google can also report differently based on when conversions are counted. Meta by default attributes conversions to the date the ad was clicked. Google by default attributes conversions to the date the conversion happened. For a 30-day window this rarely matters, but for weekly reports it can create meaningful discrepancies — especially around weekends.
How to reconcile the numbers
The cleanest approach is to pick a single source of truth and use it consistently. Here's how most agencies handle it:
| Platform | Best used for | Trust level |
|---|---|---|
| Google Analytics 4 | Total conversions and revenue (single source of truth) | Highest — neutral third party |
| Google Ads | Google search and display performance, keyword data | High — click-based, less overlap |
| Meta Ads | Creative performance, audience testing, reach | Medium — inflate due to view-through |
| TikTok Ads | Top-of-funnel metrics, video performance | Lower — most inflated, long view window |
GA4 sits outside your ad platforms and measures what actually happened on your website — so it's the most neutral view. Use GA4 for total revenue and conversion numbers in client reports. Use each platform's own dashboard for optimizing within that platform.
What to tell clients
When clients ask why the numbers differ, keep the explanation simple:
"Each platform counts conversions differently based on when they were last exposed to that platform's ads. That's normal — it's a limitation of how ad attribution works across the industry. What we use as our single source of truth is GA4, which measures actual purchases on your website. The platform dashboards tell us how to optimize within each channel."
Most clients are satisfied with this once they understand it's an industry-wide phenomenon, not an error on your part.
The bigger picture: blended view
The real solution isn't to pick which platform to believe — it's to stop looking at platforms in isolation. A customer's path to purchase almost always involves multiple touchpoints. No single platform can claim full credit accurately.
That's why the most useful metric for cross-platform campaigns isn't Meta ROAS or Google ROAS — it's blended ROAS: total ad spend across all platforms divided into total revenue from GA4. That number cuts through all the attribution noise and tells you what's actually happening.
See your blended ROAS in one view
Clean Core pulls Meta, Google Ads, TikTok, and GA4 into a single dashboard — so you can see blended performance and per-platform breakdowns without switching tabs or reconciling numbers manually.
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