If your Google Ads dashboard says 200 conversions this month and GA4 says 47, one of them is not wrong. Both are right, and they are measuring different things. The reconciliation is the interesting part.
60-word answer: Google Ads counts a conversion inside its own attribution window (30 days by default for clicks, 1 day for views) and credits the last non-direct click. GA4 uses a different attribution model (data-driven by default) and a different session window (30 minutes of inactivity). A conversion counted by Google Ads is often the same customer as a conversion counted by GA4, credited to a different source.
Hy Digital, Bangkok-based HubSpot Platinum Partner, runs tracking audits for SEA marketing teams that need the same numbers on both dashboards before their next board meeting. This post is the vocabulary and the reconciliation steps we use.
| Signal | Google Ads counts it if... | GA4 counts it if... |
|---|---|---|
| A user clicks your ad, visits the site, converts within 30 days | ✓ credited to the ad, in the ad's campaign | ✓ credited via data-driven attribution, distributed across touchpoints |
| A user sees your ad but does not click, then converts within 1 day | ✓ view-through conversion (Display / YouTube) | ✗ view-through impressions are not touchpoints in GA4 by default |
| A user clicks the ad, leaves, comes back via organic search, converts | ✓ if within Google Ads window and it was the last non-direct paid click | ✓ credited (partially) to organic search + paid search via DDA |
| Enhanced Conversions (email/phone hashed) enabled + the platform matches to a Google account | ✓ counted, sometimes without the original click | ✗ not visible in standard GA4 reports |
If the platforms use different attribution models, different windows, and different signal ingestion rules, the numbers cannot match by design. The question is not why they disagree. The question is by HOW MUCH they should disagree, and whether the gap is explainable or a signal that something is broken.
Underneath the definitional differences, three things go wrong repeatedly in SEA marketing setups.
1. The Google Ads conversion tag is set up as a Google Analytics 4 event goal WITHOUT Enhanced Conversions. This is the most common finding in our tracking audits. Google Ads is set to import a GA4 event as its conversion. The GA4 event has a 30-minute session window with no user identifier. Enhanced Conversions is off, so no email or phone match happens. Result: Google Ads only counts conversions where the user completed inside the same ad-click session — a small subset of the actual conversions. The Google Ads number under-reports.
2. The conversion event fires on a thank-you page that the user does not always reach. Many hotel and B2B forms send a lead to a third-party system (HubSpot, Salesforce, a booking engine) that redirects to a thank-you page on a different domain. If the tag is on the thank-you page and the domain switch loses the session, the conversion never fires in either GA4 or Google Ads. You will see the lead in HubSpot but not in your analytics stack.
3. Server-side tracking is set up but the Google Ads pixel is still browser-side. Server-side sends the conversion once, cleanly, from your backend. Browser-side sends the same conversion again from the visitor's browser. Deduplication is possible but is rarely configured correctly on the first pass. Result: Google Ads counts the same conversion twice for a subset of visitors and once for the rest. The number is inflated in a way that is hard to detect without an audit.
In the tracking audits we run, a gap beyond roughly 15% usually points to a misconfiguration rather than a difference in measurement philosophy. Run this reconciliation before you argue about attribution.
Step 1: Pull the same date range, the same conversion event, from both dashboards. Sounds obvious. Half of the disagreements we see are caused by comparing Ad Sessions in GA4 to Conversions in Google Ads. Confirm you are looking at the same event on both.
Step 2: Check if Enhanced Conversions is on in Google Ads. Google Ads → Tools → Conversions → click the conversion action → look for the Enhanced conversions section. If it is off, Google Ads is systematically under-counting. Turning it on requires configuring the tag to send hashed email / phone alongside the click ID.
Step 3: Check the Google Ads attribution window setting. Google Ads → Tools → Conversions → the conversion → Click-through conversion window. Default is 30 days, but many teams set it to 7 or 14 days without realizing it changes the count. A shorter window means fewer conversions credited to Google Ads.
Step 4: Check GA4's conversion event definition. GA4 → Admin → Events → look for the conversion event. Confirm it is marked as a Key event (formerly conversion). Confirm it has the same trigger as the Google Ads tag — same button, same form, same URL rule.
Step 5: Look at server-side tag counts vs browser-side tag counts. If both fire, one is a duplicate. In the audits we run, duplicate firing is the usual cause when the Google Ads number runs substantially higher than GA4 on form-fill conversions.
Neither, in isolation. For board reporting, use the CRM (HubSpot, Salesforce, or a booking engine) as the source of truth for lead volume and revenue. Google Ads and GA4 numbers are useful for CHANNEL attribution — deciding where to spend more — but they should be reconciled against the CRM at the top of every board deck.
Server-side tracking fixes the browser-blocking-tags problem and gives you cleaner signals to send to platforms with Enhanced Conversions. It does not fix attribution disagreement — Google Ads and GA4 will still use different models. Server-side is worth doing for signal quality; do not expect it to make the two dashboards match.
Directional guidance from the tracking audits we run: for form-fill and lead conversions tracked correctly, Google Ads typically runs moderately higher than GA4, typically in the region of 10 to 30%, because of Enhanced Conversions matching plus view-through credit. For e-commerce transactions with GA4 configured correctly, we usually see the gap fall into the single digits for the paid search channel. Anything bigger points at a specific setup problem, not attribution philosophy.
Start with HubSpot as ground truth for actual leads captured. Confirm the lead-capture form is firing the same event in GTM that Google Ads and GA4 import. Then reconcile Google Ads to HubSpot first, GA4 to HubSpot second. Comparing Google Ads to GA4 directly is a step later — reconcile each independently to the CRM.
Enhanced Conversions sends hashed (not readable) email and phone identifiers to Google. Whether this constitutes PII processing under PDPA depends on your cookie consent setup and lawful basis for processing. This is a question for your legal team or DPA, not for a marketing team to answer alone. Flag it before enabling.
If you have someone on the team who can run through the 5 steps above with your GTM container, Google Ads UI, and GA4 configuration open, this reconciliation is a 30-minute exercise. Most teams do not have that person available, and the misalignment costs them ad spend every month.
We run a free tracking audit that catches every issue in this post + more. We look at your Google Ads conversion setup, your GA4 event configuration, your GTM container, your server-side tags (if any), and the CRM handoff. You get a report within 5 business days with the exact fixes ranked by impact on your dashboards.
Book the free tracking audit: hy.digital/free-tracking-audit
Prefer a broader conversation about your whole marketing measurement stack? Book a free consultation: hy.digital/free-consultation
Hy Digital is a Bangkok-based HubSpot Platinum Partner. We audit tracking setups for SEA marketing teams who need their dashboards to make sense before their next board meeting.