Google Ads conversion tracking: how to set it up, verify it and date every change

What is Google Ads conversion tracking and how does it work?

Google Ads conversion tracking counts the valuable actions people take after clicking or viewing your ads: a purchase, a lead form, a sign-up or a call. Those counts feed your reports and, when an action is set as primary, Smart Bidding.

Each thing you count is a conversion action. A conversion action has a data source (the Google tag on your site, an event imported from GA4, an offline import or calls) and settings that decide how it is counted: category, value, count, conversion window and whether it is primary or secondary.

That second part is where most reporting surprises come from. The tag can work perfectly while a settings edit quietly changes what lands in the "Conversions" column. So treat Google Ads conversion tracking as two jobs: getting the data in, and keeping a dated record of every change to how it is counted. Our Google Ads change history guide covers what the account records on its own.

How do I set up Google Ads conversion tracking?

Start in Google Ads under Goals > Summary, select "+ Create conversion action" and follow Google's three steps: data source, conversion actions, next steps. You need Admin access in Google Ads, plus Edit access in the GA4 property if you import from it.

1. Data source. Under "Conversions on a website", enter your domain and select Scan. Google Ads looks for an existing Google tag or a linked Google Analytics property. If it finds neither, select Set up to create a Google tag.
2. Conversion actions. Choose a category (purchase, submit lead form and so on), then create the action from the Google tag or from GA4 events.
3. Primary or secondary. Mark each action as primary (used for bidding) or secondary (observation only).
4. Next steps. Add the tag if you don't have one, turn on enhanced conversions if you plan to use them, and select Agree and finish.

With the Google tag you have three ways to define the action:

• "Automatically without code" counts a page load by a URL rule ("URL is", "URL contains" or "URL starts with"), for example a thank-you page.
• "Manually using code" adds an event snippet through the Google tag or Google Tag Manager. Use it for button clicks, dynamic values and transaction IDs.
• "Use Google Tag Manager" sends the setup to a GTM container, where you add the tags, triggers and variables and publish.

One warning from Google's own setup guide: if a CMS plugin already manages your tags, adding the tag again by hand causes duplicate reporting. If that has already happened, see how to find and fix duplicate conversions.

Google tag, GA4 import or enhanced conversions: which should you use?

Use the Google tag when you want Google Ads to own the measurement, GA4 import when your team already reports from GA4 key events, and enhanced conversions on top of either to improve measurement with hashed first-party data. They are not exclusive: enhanced conversions supplement your existing tracking.

Enhanced conversions send first-party data such as an email address, hashed with SHA256 before it leaves your site. Google asks you to trim spaces, lowercase text and format phone numbers to E.164 before hashing. There are two types: enhanced conversions for web (sales on your site) and for leads (offline sales that start with a website lead).

Whichever source you choose, don't count the same action from two sources as primary. If GA4 and Google Ads numbers still disagree, this breakdown of why GA4 and Google Ads conversions differ explains the usual reasons.

How do I check that conversion tracking is working?

Go to Goals > Summary, find the action in the "Name" column and read the "Status" column in the same row. Click a status, then "View details", to see the issues Google found.

A status tells you whether data arrives, not whether it is right. To see which tags actually fire on a page, use Tag Assistant (our Tag Assistant walkthrough). Then complete one real test conversion and confirm it shows up against the right action, with the right value.

Which tracking edits change your reported conversions?

Several settings edits change the "Conversions" column without any change in customer behaviour. Most apply only from the date of the edit, so the same report can mix data counted under two different rules.

• Primary to secondary, or back. Primary actions are reported in "Conversions" and used for bidding; secondary actions appear only in "All conversions". Moving an action changes your headline number and what Smart Bidding optimizes for. Google also notes that frequent goal changes reset the learning window.
• Count. "Every" counts every conversion after an ad interaction; "One" counts one per click. Google recommends Every for purchases and One for leads. Changes apply only to future reporting.
• Conversion window. The click-through default is 30 days, adjustable from 1 day up to 30, 60 or 90 days depending on the source. Changes are not retroactive.
• Source edits. A new GTM version, a changed thank-you URL, a consent banner update or a CMS plugin that adds its own tag. These happen outside Google Ads, so its change history won't show them. A banner change can look exactly like a demand drop (how to prove a consent banner caused it).

Example: a client asks why leads jumped 40% in one week while sales stayed flat. Lining up the changes from the days before shows that on Monday a GA4 "generate_lead" import was set to primary, next to the existing Google tag form action. Both were counting the same form. Setting the GA4 import back to secondary brought the numbers back in line. (Names and numbers are illustrative.)

How do I isolate which change caused a jump or drop in conversions?

Rule out tracking first, then put every change from the days before the shift on one timeline and test one explanation at a time. A conversion count that moves overnight is more often a measurement change than a market change.

1. Rule out tracking
2. Line up every change
3. Match dates to the shift
4. Test one hypothesis

Start with the date the metric moved. Compare "Conversions" with "All conversions": if only one of them moved, look for primary or secondary edits. Check each action's status, and whether a tag, GTM container or site template was published that day. Then check the bidding side: did a target, budget or campaign change land at the same time?

The hard part is that the evidence sits in different places. Google Ads change history shows account edits for the past 2 years, but Google notes that not all account-level settings changes may be listed, and GTM, the site and the consent banner keep their own records. With every change on one timeline, you would see that the thank-you URL changed the same afternoon conversions dropped, instead of rebuilding that from four tools. In Changeline, Google Ads edits are imported automatically through a read-only connection, and the team logs tag, site and consent changes next to them.

For the conversation that follows, see how to explain a conversion drop to a client.

How should you document conversion tracking changes?

Record every change to a conversion action or its source on the day it happens: who, what, before and after, and why. A one-line entry today saves a day of digging next month.

• Date and time of the change, with the time zone
• The conversion action affected
• What changed, before and after (for example, count Every to One, window 30 to 60 days)
• Where it changed: Google Ads, GA4, a GTM version, the site or the consent banner
• Owner and reason
• When to judge the effect, keeping in mind that conversions can arrive days after the click, within the conversion window

Keep the log per client or account and share it with whoever reports the numbers. Our marketing change log template has the columns ready, and the marketing change log guide explains how to make logging a team habit. Tag containers deserve the same discipline: GTM version history shows who published what and when.