When Google Ads under-reports conversions, Smart Bidding optimises on partial data. When it over-reports, budgets scale on results that never happened. Both are tracking problems first.
This is the Google Ads companion to my Meta Pixel and CAPI guide. It covers the checks I run when conversions are missing, duplicated or don't match the CRM.
1. Common reasons conversions go missing
- The conversion tag fires on a page users don't reach, such as a skipped thank-you page.
- Consent mode blocks tags without modelling configured.
- Both a Google Ads tag and an imported GA4 conversion count the same action as primary.
- The conversion action is set to Secondary, so it is not used for bidding.
- Cross-domain checkouts drop the click ID (
gclid).
2. Google Ads tag vs GA4 import
| Google Ads tag | GA4 import | |
|---|---|---|
| Speed of reporting | Faster | Can lag by hours |
| Attribution | Google Ads model | GA4 model, then imported |
| Risk | Separate setup to maintain | Double counting if both are primary |
Pick one primary source per action. Keep the other as Secondary for observation.
3. How to verify conversions
- Use Google Tag Assistant to confirm the tag fires once on completion.
- Check the conversion action's status in Google Ads: Recording, No recent conversions or Inactive.
- Run a test conversion and confirm it appears in GA4 DebugView.
- Compare a day of CRM leads or orders with recorded conversions.
4. Setting up enhanced conversions
Enhanced conversions send hashed first-party data, such as email or phone, with the conversion so Google can match more of them.
- Enable enhanced conversions in the conversion action settings.
- Pass normalised email and phone through the tag or Google Tag Manager.
- Accept the customer data terms in Google Ads.
- Check the diagnostics tab for match coverage warnings.
5. Importing offline and CRM conversions
For lead generation, import qualified leads or sales from your CRM so bidding optimises for real outcomes. Store the gclid with each lead and upload status changes regularly.
6. Google Ads tracking checklist
Conversion tracking checklist
- One primary conversion source per action.
- Tag fires once per completion.
- Conversion value and currency are correct.
- Consent mode configured.
- Enhanced conversions enabled and matching.
gclidpreserved across domains and stored in CRM.- Offline conversions uploaded for lead generation.
Conclusion
Clean conversion data is the foundation of Smart Bidding. Choose one source of truth, recover lost matches with enhanced conversions and feed real business outcomes back to Google Ads.
Frequently asked questions
Why does Google Ads show different conversions from GA4?
They use different attribution models, reporting dates and counting settings. Some difference is normal; large or sudden gaps point to a tracking problem.
Do enhanced conversions work with consent mode?
Yes, but only for users and data you are permitted to process under your consent setup and privacy obligations.
Why are my conversions duplicated?
Usually because both a Google Ads tag and an imported GA4 conversion count the same action as primary, or the tag fires on page reloads.