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How to Set Up Google Ads Conversion Tracking Through GTM

Google Ads bidding is only as good as the conversions you feed it, and the most common fault is not missing data but duplicated data — the same enquiry counted once through a GA4 import and again through a direct conversion tag, with nobody aware both routes are live. This guide sets up conversion tracking deliberately, picks one route rather than two, and verifies the result.

1. 1

   Decide on one route before you build

   There are two ways to get conversions into Google Ads: import them from GA4, or send them directly with a Google Ads conversion tag. Both work. Running both for the same action double counts it. Choose one per action and write down which you chose.

2. 2

   Audit what is already counting

   Open Google Ads conversion actions and list everything there, including anything inherited from a previous agency or set up years ago. Note the source of each. This step alone resolves most reported conversion discrepancies without changing anything.

3. 3

   Link Google Ads and GA4 if you are importing

   If you chose the GA4 import route, link the two products first, then import the specific key events you want. Only import the ones that represent real commercial intent — the import screen will happily offer you every event you have ever sent.

4. 4

   Create the conversion action and get its identifiers

   If you chose direct tagging, create the conversion action in Google Ads and note its Conversion ID and Conversion Label. Those two values are what the tag needs, and mixing up labels between actions is a quiet, hard-to-spot error.

5. 5

   Add the conversion linker before anything else

   Install a conversion linker tag firing on all pages. It stores the ad click information that attribution depends on. Without it, conversions get recorded but a share of them cannot be attributed to the click that caused them, which looks like poor ad performance rather than a tracking gap.

6. 6

   Build the conversion tag on the trigger you already made

   Reuse the trigger you built for your GA4 event rather than creating a parallel one. Two triggers watching the same action is how the two drift apart over time, with one updated and one forgotten.

7. 7

   Set counting and attribution deliberately

   Choose whether the action counts once per click or every time, set the conversion window, and decide whether this action is primary or secondary. Primary conversions steer automated bidding; secondary ones are for observation. Many accounts have this backwards without knowing.

8. 8

   Verify with a real conversion and the diagnostics

   Complete a genuine conversion yourself, then check it appears in Google Ads. Use the conversion action diagnostics to confirm no warnings about tag or linker problems. Allow for reporting delay before concluding something is broken.

9. 9

   Re-check the total against your CRM

   A week later, compare recorded conversions against actual enquiries in your CRM. They will not match exactly and should be in the same neighbourhood. A conversion count that materially exceeds real enquiries is the signature of the double-counting this guide exists to prevent.