Why GA4 and Google Ads conversions don’t match
GA4 and Google Ads are two witnesses to the same event, and they were standing in different places. GA4 (Google Analytics 4, the tool that reports on your website) watches what happens on the site and can share the credit between every channel that brought someone there. Google Ads only reports conversions it can tie to one of its own ads.
So the two will rarely match, and a steady difference between them is normal. A gap needs looking at when it changes suddenly, when Google Ads claims more sales than your business actually took, or when one of the two stops recording altogether.
A conversion, if the word is new to you, is a result you’ve told the system to count, such as a sale or an enquiry. The referee in all of this is your own order system or CRM (the software holding your customer and sales records), because it knows what really happened. We don’t sell GA4 reporting or dashboards, so this page sticks to what the gap says about whether your ad tracking can be trusted.
Why do they count differently?
None of the reasons below is a fault. They’re differences in how each product was designed.
They file sales under different days. Google Ads puts a conversion against the day of the ad. GA4 puts it against the day it happened. Someone who clicks on Monday and buys on Thursday ends up in two different places, so a single day or week can look badly out while both systems are right.
They give credit differently. Google says Google Ads only reports conversions where there was an interaction with its ads. GA4 can hand that same sale to an email, an organic search result or a return visit.
They treat repeats differently. Each conversion in Google Ads is set to count either “every” time or just “one” per click, while GA4 may record every occurrence of the event.
You may be reading the wrong column. The standard Conversions column in Google Ads only includes actions set as primary, meaning the ones used for bidding. Secondary actions are for observation only, and people who saw an ad without clicking it are left out by default. Compare against the wrong column and you’ve built yourself a gap.
Google Ads estimates some conversions. When someone clicks an ad on their phone and buys on a laptop, Google models that link. GA4 won’t necessarily see those two visits as the same person.
They have different time limits. Every Google Ads conversion action has a conversion window, the period after a click during which a sale can still be counted. A slow decision can fall outside it in Google Ads and still show up in GA4.
Invalid clicks get removed. Google filters out clicks it treats as spam or accidental, and can take away the conversions that went with them. GA4 will still have recorded those visits.
Consent changes what each one can see. Visitors who refuse cookies are measured differently, and as far as we’re aware the two products don’t estimate those missing people in the same way.
Give the figures time to settle as well. Google suggests allowing a day or two for the two products to sync, and says data can take several days to fully appear after big changes or after linking accounts.
How do you compare them fairly?
Most alarming comparisons turn out to be unfair ones, so set this up properly before you draw any conclusions.
- Pick a longer period. A few weeks smooths out the problem of sales being filed under different days. Leave out the last few days, which are still filling in.
- Use the right Google Ads column. Add “Conversions (by conv. time)”, which files each conversion under the day it happened, as GA4 does.
- Compare one thing at a time. Put purchases against purchases, and not every conversion against every key event (GA4’s name for the actions you’ve marked as important).
- Look only at Google Ads traffic in GA4. Otherwise you’re comparing ad sales with sales from every channel you run.
- Bring in the referee. Put your real orders or qualified enquiries for the same period next to both figures.
Which gaps are normal, and which need looking at?
| What you see | Verdict | What it usually means |
|---|---|---|
| A difference that stays much the same month after month | Normal | The two products are applying their different rules consistently |
| Single days that look wildly out while the month is close | Normal | Sales filed under different days |
| GA4 shows fewer paid conversions because email or organic got the credit | Normal | Different rules for who gets the credit |
| The last few days look low in Google Ads, then fill in | Normal | Late conversions being added to the day of the ad |
| The gap jumps on a particular date and stays there | Look at it | Something changed: a website release, a tag, a cookie banner or a setting |
| Google Ads reports more sales than you actually took | Look at it | Probably the same sale being counted twice |
| Google Ads visits appear in GA4 as direct or “(not set)” | Look at it | Auto-tagging, which adds a click code to your ad links, may be off or a redirect may be stripping the code |
| One of the two shows nothing at all | Look at it | A broken tag, or a lost link between the accounts |
| The gap only appears on one device, browser or form | Look at it | A fault on that page or journey |
You’ll see people quote an acceptable percentage for this gap. We won’t, because a normal gap depends on your sales cycle, how many visitors accept cookies and how much of your marketing happens outside Google Ads. The pattern tells you far more. A gap that holds steady is usually two systems applying different rules, while a gap that moves usually means something changed.
Should you import GA4 conversions into Google Ads?
You can, and on a small account with no developer to hand it’s a reasonable way to get going. Importing means Google Ads receives a conversion from GA4 instead of from its own tag, a tag being a small piece of tracking code on your site.
The catch arrives when a GA4 import and a Google Ads tag measure the same sale and both are set as primary, because Google Ads then counts that sale twice. Choose one as primary and leave the other as secondary, so that you can still compare them without affecting bidding. It’s also easy to run into this without meaning to, as linking the accounts and importing an event takes only a few clicks and you may get no obvious warning that a tag is already measuring it.
Importing doesn’t make the gap go away either. The figures in Google Ads will still follow its own rules about dates, credit and counting, even when the data started life in GA4.
What should you do about a gap you can’t explain?
Start by finding the date it began, because a date gives you something to investigate. Line it up against website releases, changes to your cookie banner and anything published in Google Tag Manager, the tool many websites use to hold their tags. Google Ads also keeps a change history, a log of the edits made to your account, which can show whether a setting was altered on the same day.
If nothing lines up, work through this Google Ads tracking audit checklist, which covers the things most likely to have moved and marks the parts that need a developer.
Don’t try to force the two numbers to agree. Adjusting settings until the reports look the same can hide a real problem and may make your bidding worse, and a matching pair of figures doesn’t prove that either of them is correct. What you want is an explanation for the difference that holds up against your real orders.
If you’d rather hand it over, our Tracking Audit looks at the gaps between GA4 and Google Ads along with your tags, conversion counting, enhanced conversions and consent. It’s a fixed price from £395 and ends with a traffic-light report on what’s fine and what isn’t. A short call is enough to find out whether it makes sense for you.