I’m experiencing an issue with configuring the integration between HubSpot conversion events and Google Ads.
I’ve created events such as HubSpot – Lead, HubSpot – Marketing Qualified Lead, etc. However, on the Google Ads side, I sometimes see only 1-2 conversions, which is significantly lower than the numbers shown in HubSpot. Additionally, I don’t see any “Last sync” status in HubSpot for these events.
Has anyone encountered a similar issue? What could be the possible reasons for this discrepancy?
I’d really appreciate your thoughts and suggestions.
Hi @OBudai and thanks so much for reaching out and sharing your question with the HubSpot Community.
It’s not uncommon to notice discrepancies between HubSpot and Google Ads conversion numbers. This can sometimes be due to differences in how each platform tracks and attributes conversions, or delays in syncing the data.
If you’re not seeing a “Last sync” status for your events, it might be worth double-checking the integration settings or re-authenticating the connection.
I’m tagging some of our experts to see if anyone has tips or solutions to share. Hi @danmoyle, @Lucila-Andimol and @TomM2 do you have suggestions to help @OBudai, please?
Thanks so much in advance for your valuable contributions and have a lovely day!
Bérangère
Welcome to the Community @OBudai! It’s a tale as old as time, it seems. I’ve heard this since I started using HubSpot back in 2010. Two different systems rarely sync perfectly. Here’s what’s going on. Different attribution models lead to mismatches. HubSpot counts net-new contacts via its tracking cookie and UTMs, while Google Ads attributes based on click/view-through windows and may count repeat events per user. No GCLID (Google Click ID) captured on contacts, lack of hashed customer data sharing (e.g., email/phone), or using a Google Ads Manager/MCC account prevents syncing for enhanced conversions. Delays in sync (up to 48 hours for enhanced conversions activation), ad blockers, cross-domain issues, or time zone differences can reduce counts in Google Ads.
Here are a few troubleshooting steps you could take.
Navigate to Marketing > Ads > Events in HubSpot; verify events are toggled on, review details, and check for “Update to EC” prompts to enable Enhanced Conversions for Leads.
In Google Ads, go to Tools & Settings > Conversions; ensure enhanced conversions is on (API method), and confirm events appear as conversion actions with “Included in conversions” set to Yes.
Re-authenticate the integration: Settings > Marketing > Ads > Troubleshoot > Re-sync, using a Google user with full admin rights.
Confirm contacts have GCLID property populated and consent/data sharing enabled in event settings; test with a recent lifecycle change.
I looked up some best practices to hopefully prevent this as best you can, and here’s what I found. Use “All contacts that move to the selected lifecycle stage(s)” for syncing to maximize ad optimization data, and monitor for UTM consistency via HubSpot’s auto-tracking. Note that exact 1:1 matches aren’t expected due to platform differences. HubSpot lacks sync logs without errors. For persistent issues, share a non-syncing contact example in HubSpot Community for deeper review.
Thank you very much for your detailed response. I can now see the last sync date, however, the discrepancy between the two tools is quite significant. Could you please share the level of difference you experienced on your side, just for comparison?
Thanks,
Alyona
Hi @OBudai. It’s been a bit since I’ve been that granular with this set up, and when I was it wasn’t a standard deviation. But if I recall correctly, the difference of “normal” cross-platform gaps were anywehre from like 5% to 20% range. If they’re consistently above about 25% I’d be concerned.
A 20–30% discrepancy between HubSpot and Google Ads is generally considered normal once the integration is properly configured. If you’re seeing closer to 50% or more, that usually points to a specific fixable issue rather than just platform differences.
The most common culprit for large gaps is GCLID coverage. If only a portion of your contacts have the GCLID property populated (which you can check with a HubSpot contact filter), then only those contacts can fire conversion events back to Google. Everything else goes silent. In practice, GCLID capture depends on whether the visitor clicked a Google Ad in that same session and whether your HubSpot tracking code fired before the form submission, both of which can fail more often than expected.
A quick way to sanity check: look at what percentage of your recent MQL/SQL contacts actually have a GCLID value. If it’s below 60–70%, that gap explains most of your discrepancy and the fix is on the tracking setup side rather than the sync configuration.
The other thing worth knowing: the numbers will never match, and trying to reconcile them exactly is a losing battle. The more useful frame is whether the conversion signals you’re sending to Google are representative enough for Smart Bidding to optimize on. Even partial data is better than none.
I’ve heard this since I started using HubSpot back in 2010. Two different systems rarely sync perfectly. Here’s what’s going on. Different attribution models lead to mismatches. HubSpot counts net-new contacts via its tracking cookie and UTMs, while Google Ads attributes based on click/view-through windows and may count repeat events per user. No GCLID (Google Click ID) captured on contacts, lack of hashed customer data sharing (e.g., email/phone), or using a Google Ads Manager/MCC account prevents syncing for enhanced conversions. Delays in sync (up to 48 hours for enhanced conversions activation), ad blockers, cross-domain issues, or time zone differences can reduce counts in Google Ads.