Your Google Ads dashboard shows 85 conversions. GA4 shows 60. You’ve triple-checked the setup. Both platforms are connected to the same store. The numbers will never match—and that’s not a bug. A 20-30% discrepancy between GA4 and Google Ads is considered normal by analytics professionals.
The gap exists because these platforms measure different things in different ways. Google Ads optimizes for advertising performance. GA4 measures site-wide behavior. They answer different questions with different methodologies. Here’s exactly why the numbers differ and what to do about it.
Why the Numbers Will Never Match
Five fundamental differences make matching numbers impossible. Understanding these stops the frustrating hunt for configuration errors that don’t exist.
1. Click-Date vs Event-Date Attribution
Google Ads attributes conversions to when the ad was clicked, not when the purchase happened. A customer clicks your ad on Monday, browses, then buys on Friday. Google Ads records that conversion on Monday. GA4 records it on Friday.
This creates permanent timing mismatches. If you run a big campaign on Monday generating clicks that convert throughout the week, Google Ads shows Monday as your best day. GA4 spreads those conversions across the actual purchase dates. Neither is wrong—they’re answering different questions.
2. Conversion Counting Settings
Google Ads lets you choose between counting every conversion or one per user. GA4 typically counts unique users. If a customer makes three purchases from one ad click, Google Ads might count three conversions. GA4 counts one converting user.
For e-commerce, “every conversion” often makes sense—you want to know total purchases, not just unique buyers. But this creates another built-in gap between platforms.
3. Processing Latency
GA4 has 24-48 hour processing latency while Google Ads reports near-real-time. Check your numbers Monday morning and you’re comparing Google Ads’ current data against GA4 data that’s still being processed. The gap often narrows after waiting 48 hours.
This catches store owners constantly. They see mismatched numbers, panic, start debugging—when the actual answer is patience.
4. Modeled Conversions Fill Different Gaps
Both platforms use machine learning to estimate conversions they can’t directly measure. But their models work differently.
Google Ads over-attributes by 15-20% when Enhanced Conversions or Consent Mode V2 kicks in for modeled conversions. It’s trying to account for users who didn’t consent to tracking but likely converted based on aggregate patterns.
GA4 underreports conversions by 18-35% for paid campaigns when cookies are rejected or blocked. Its behavioral modeling requires traffic thresholds most smaller stores never reach.
Translation: Google Ads tends to estimate high. GA4 tends to estimate low. The gap is baked into their algorithms.
5. Attribution Model Differences
GA4 defaults to data-driven attribution across all channels. Google Ads uses its own attribution model optimized for ad performance. When a user interacts with organic search, email, and a paid ad before converting, each platform allocates credit differently.
Google Ads naturally favors giving credit to ads—that’s what it’s designed to optimize. GA4 spreads credit across the journey. Same conversion, different allocation.
You may be interested in: Why Your GA4, Google Ads, and Facebook All Show Different Conversion Numbers
What “Normal” Actually Looks Like
A 20-30% difference between GA4 and Google Ads conversion tracking is considered normal. If Google Ads shows 100 conversions and GA4 shows 70-80, your tracking is probably working correctly.
When should you investigate? If the gap exceeds 40%, something may be misconfigured. Common culprits include:
- Different conversion actions: Google Ads tracking purchases while GA4 tracks thank-you page views
- Missing conversion linker: GA4 and Google Ads not sharing user identifiers properly
- Duplicate events: Multiple tags firing the same conversion
- Consent mode misconfiguration: Different consent states affecting each platform differently
But if your gap is 20-30%? That’s the platforms working as designed.
Which Platform to Trust (And When)
Stop trying to reconcile the numbers. Start using each platform for what it does best.
Use Google Ads data for ad optimization. The bidding algorithms learn from Google Ads conversion data. Feeding them GA4 data instead can actually hurt performance because you’re training the model on different signals than it expects.
Use GA4 for cross-channel analysis. When you need to understand how paid ads interact with organic, email, and direct traffic, GA4’s multi-channel view is what you need.
Use WooCommerce as your source of truth. Neither platform knows your actual revenue as accurately as your own database. When calculating true ROAS, use WooCommerce order totals—not platform-reported revenue that’s subject to modeling, attribution differences, and tracking gaps.
You may be interested in: When Does WooCommerce Fire Your Conversion?
Making Platform Discrepancies About Methodology, Not Data Quality
Here’s the real problem: when both platforms receive different event data, you can’t tell whether discrepancies come from methodology differences or data quality issues.
Ad blockers block GA4’s tracking script for 31.5% of users globally. Those conversions never reach GA4 but might reach Google Ads through Enhanced Conversions. Safari’s 7-day cookie limit breaks attribution chains for both platforms differently. Consent Mode affects each platform based on its specific implementation.
Server-side tracking solves this by sending identical event data to all platforms simultaneously. Transmute Engine™ captures conversions at the WooCommerce order hook—server-side, before any browser-level blocking can interfere. GA4, Google Ads, Facebook, and BigQuery all receive the exact same purchase event.
The methodology differences remain—Google Ads still uses click-date attribution while GA4 uses event-date. But at least you know both platforms started with identical raw data. Any discrepancy comes from how they process events, not whether they received them.
Key Takeaways
- 20-30% discrepancy is normal. Stop debugging what isn’t broken.
- Click-date vs event-date attribution creates permanent timing gaps—Google Ads credits the click, GA4 credits the conversion moment.
- Google Ads tends high (15-20% over-attribution from modeled conversions). GA4 tends low (18-35% underreporting when cookies blocked).
- Use each platform for its purpose: Google Ads for ad optimization, GA4 for cross-channel analysis, WooCommerce for true revenue.
- Server-side tracking ensures identical source data to all platforms—discrepancies become methodology differences, not data quality questions.
No. A 20-30% discrepancy between Google Ads and GA4 is normal and expected. The platforms use different attribution models, different counting methods, and different timing. Your tracking is likely working correctly—the platforms simply measure conversions differently by design.
Industry professionals consider 20-30% difference between GA4 and Google Ads to be normal. If your discrepancy falls within this range, the platforms are working as designed. Larger gaps may indicate configuration issues worth investigating.
Use Google Ads data to optimize your ad campaigns since its data directly informs the bidding algorithms. Use GA4 for cross-channel analysis and understanding user journeys across all traffic sources. Use WooCommerce actual orders as your source of truth for real revenue.
Google Ads can show higher numbers for several reasons: it may count every conversion including repeat purchases, it uses click-date attribution which clusters conversions on busy ad days, and Enhanced Conversions models additional conversions from users who didn’t consent to tracking. These aren’t fake conversions—they’re different measurement approaches.
Stop chasing matching numbers. Start using each platform for what it does best—and ensure they all receive the same source data. Learn how server-side tracking unifies your conversion data.
