Key takeaways
- Google Ads and GA4 are built to answer different questions, so they will rarely match. A gap is usually a settings difference, not broken tracking.
- The biggest causes are attribution model and channel credit, click date versus conversion date, counting settings, and modelled conversions.
- Use Google Ads primary conversions for bidding. Use one agreed source per question for reporting, and say which one in every report.
- Before you explain a gap to your boss, line up the date basis, the conversion action and the attribution settings. Most of the gap often closes.
Your boss opens two reports. Google Ads says 142 leads last month. GA4 says 97 from Google Ads. Now they want to know which number is real, and whether the agency or the ad platform is inflating results.
Both numbers can be correct. Google Ads and GA4 count, date and credit conversions differently on purpose. This article explains each cause in plain terms, shows how to line the reports up, and gives you a decision guide for which number to use for bidding and which to use in reports.
Why the two tools disagree by design
Google Ads measures one thing: what happened after someone interacted with your Google ads in that account. GA4 measures everything that happens on your site, from every channel. Google’s own GA4 help page says conversions focus on advertising return across channels, while key events focus on traffic acquisition and user behaviour. Different jobs, different rules.
That shows up in six main places.
The six main causes of the gap
1. Attribution model and which channels get credit
In Google Ads, data-driven attribution is the default for most conversion actions. Last click is the only other option. Data-driven can split credit across several ad clicks, so a campaign can be credited with 0.4 of a conversion.
In GA4, the attribution settings decide which channels compete for credit. With Paid and organic channels, organic search, email and social can take the credit Google Ads would otherwise claim. With Google paid channels, only Google Ads gets credit. Google says Analytics reports default to Paid and organic, while the conversions GA4 shares with Google Ads default to Google paid channels. Also, Google Ads only reports conversions from its own account’s interactions. If a lead clicked your ad, then came back through a newsletter, GA4 may credit the newsletter.
Key event reports in GA4 add another layer. Google explains that key events credit the session start using last non-direct click, while GA4 conversions are event-scoped and can use data-driven attribution.
2. Click date versus conversion date
This one surprises most people. By default, Google Ads reports a conversion on the date of the ad interaction. GA4 reports it on the date the action happened. If someone clicks on October 28 and fills in your form on November 3, Google Ads puts it in October and GA4 puts it in November.
For businesses with a long consideration period, like B2B services, renovations or post-secondary programs, this alone can move a lot of conversions between months. Google also notes that conversions can be reported up to 90 days after the click, so last month’s Google Ads total can keep rising after the month ends.
The fix is easy: in Google Ads, add the Conversions (by conv. time) column. It dates conversions the way GA4 does.
3. Counting settings
In Google Ads, each conversion action counts either Every conversion or One conversion per ad interaction. If someone submits your form three times, Every counts three and One counts one. GA4 has its own counting method setting, which Google lists as a cause of gaps between conversions and key events. Check both. For lead generation, One is usually the right setting in Google Ads. For purchases, Every usually is.
4. Primary, secondary and what is in the column
The Google Ads Conversions column only includes primary conversion actions. Secondary actions appear only in All conversions. Google warns that minor actions like page views or add to cart, if set as primary and given a value, can inflate totals. Before comparing, make sure you are comparing the same action in both tools, not “all leads” in one and “contact form only” in the other.
5. Consent, modelling and thresholds
When visitors decline cookies, neither tool can observe them directly. Google Ads uses consent mode modelling to estimate conversions from unconsented users, and those modelled conversions appear in the Conversions column. Google says accounts need consent mode set up correctly and a threshold of 700 ad clicks over seven days, per country and domain grouping, to be eligible. GA4 has its own behavioural modelling for consent mode. The two tools model separately, so their estimates differ.
Google Ads also models cross-device conversions, for people who click on a phone and convert on a laptop.
GA4 also applies data thresholds. When a report includes demographic data or search query information, GA4 may withhold rows with too few users to protect privacy. A notice at the top of the report tells you when this happens. Widening the date range can help. Thresholding hides rows in GA4. It does not change what Google Ads reports.
If your site uses a consent banner, as many Canadian sites do, especially for Quebec visitors, expect the gap to grow as more people decline. That is a measurement limit, not lost leads.
6. Imported versus native conversions
You can track Google Ads conversions with the Google Ads tag, or import GA4 key events into Google Ads as conversions. Google says imported GA4 data can take up to 24 hours to appear, and conversions created from GA4 start as secondary, so they won’t affect bidding until you change them. Google Ads also filters invalid clicks, and its cookies last 90 days compared with up to two years for GA cookies. All of these shift totals.
How to line the reports up
When someone asks why the numbers differ, work through these steps before you answer.
- Pick one conversion action. Compare a single action, like “Quote request,” in both tools. Use the same event name everywhere.
- Use a closed date range. Pick a full past month. Google says data can take 24 to 48 hours to sync, and up to seven days after major changes.
- Match the date basis. In Google Ads, add Conversions (by conv. time).
- Match channel credit. In GA4, go to Admin, Data display, then Attribution settings and check the model and channels. Google says channel changes apply going forward to all linked Google Ads accounts, so check these settings rather than changing them just to make a report match.
- Check counting. Confirm One versus Every in Google Ads and the counting method in GA4.
- Check the basics. Confirm auto-tagging is on and that redirects aren’t stripping the GCLID. Without it, paid visits can show up in GA4 as organic or direct.
- Write down the remaining gap. Whatever is left after this is mostly modelling, cross-channel credit and cookie differences. Report it as an expected range, not an error.
A worked example
The numbers are illustrative. A Halifax accounting firm sees 142 quote requests in Google Ads for October and 97 attributed to Google Ads in GA4.
- Switching to Conversions (by conv. time) drops Google Ads to 131. Eleven leads clicked in late September but converted in October, or clicked in October and converted in November.
- The Google Ads action was set to count Every, and nine people submitted the form twice. Counting each person once brings it to 122. The firm switches the action to One so future months count unique leads.
- In GA4, the report used Paid and organic channels. Checking the conversion paths shows 11 leads clicked a Google ad first, then came back through organic search or email, which took the credit. Counting those gives 108.
The gap shrank from 45 to 14. The rest is mostly modelled conversions and consent. The firm’s CRM shows 112 real quote requests from paid search that month, which sits between the two. That is the number that goes to the partners, with the platform figures as context.
Which number to trust: a decision guide
There is no single right number. There is a right number for each question.
| The question | Use this | Why |
|---|---|---|
| What should Smart Bidding optimize toward? | Google Ads primary conversions | Only primary actions drive bidding. Modelled and cross-device conversions give the bidder more complete data. |
| Is a Google Ads campaign working compared with last month? | Google Ads, by conversion time | Consistent rules over time, and month totals change less after the month closes. |
| How do channels compare: Google, Meta, email, organic? | GA4, Paid and organic channels | One set of rules for every channel. Each ad platform credits itself. |
| How many real customers or qualified leads did we get? | Your CRM or sales system | Neither tool knows which leads were junk or which closed. |
| What does the finance team book? | Your CRM or e-commerce platform, by transaction date | Finance works on transaction dates and actual revenue in CAD. |
Rules of thumb
- If you bid with Smart Bidding, keep the Google Ads tag or a well-maintained GA4 import as primary, but not both for the same action. As an editorial rule, we make one source primary per action to avoid counting the same lead twice in bidding.
- If lead quality is a problem, import qualified leads or sales from your CRM and make those primary. That fixes more than any attribution setting.
- If your boss compares platforms, report from GA4 or your CRM. Don’t add up Google Ads and Meta conversions. Each platform claims credit by its own rules, so the sum overstates results.
Common mistakes
- Treating any gap as a tracking failure. Some gap is normal. A sudden change in the gap is what deserves investigation.
- Switching attribution to make numbers match. In Google Ads, changing the model affects automated bidding and only applies going forward. Don’t change it for reporting comfort.
- Closing the month too early. Google Ads keeps adding conversions to past click dates. Pull monthly reports a few days after month end, or use conversion-time columns.
- Comparing different actions. “Leads” in one tool and “contact form” in the other will never match.
- Ignoring sessions versus clicks. Clicks and sessions are different metrics. Google notes that repeat clicks can merge into one session, and returning visitors can create more sessions than clicks.
What to tell your boss
Keep it short. Here is a script you can adapt: “Google Ads counts conversions on the day of the ad click and only credits Google ads. GA4 counts them on the day they happen and shares credit with organic search and email. We use Google Ads numbers to run the bidding, GA4 to compare channels, and the CRM as the official lead count. This month the CRM shows X real leads from paid search.”
Your next step: pick last month, add the Conversions (by conv. time) column, check GA4’s attribution settings, and write down which source answers which question. Share that one-page note with your boss before the next report goes out.
Sources: Data discrepancies: factors and troubleshooting, Google Ads Help · Create conversions from Google Analytics events in Google Ads, Google Ads Help · About attribution models, Google Ads Help · About consent mode modelling, Google Ads Help · Conversions vs. key events in Google Analytics, Analytics Help · Select attribution settings, Analytics Help · Change the reporting attribution model for key events, Analytics Help · About data thresholds, Analytics Help · Clicks and sessions discrepancy for Google Ads and Google Analytics, Analytics Help
Platform details as of November 2026.