Google Ads Conversion Tracking: Tag vs GA4 Import

If you run Google Ads for a small business, conversion tracking is the setting that tells the system which clicks led to something you care about: a purchase, a form submission, a call. This guide is for small advertisers, bloggers and agency owners who need to set it up for a website and want to choose between the two main routes. Everything below follows Google’s own Help pages, and menu names are quoted as those pages currently give them. Google changes its interface often, so check labels against your own account.

Contents

Why conversion tracking comes first

Google’s guidance on primary and secondary actions warns that incorrect settings can stop Smart Bidding from optimising well, so the choices you make during setup matter well beyond reporting. If you plan to use automated bidding, read our guide to the Smart Bidding learning period after you finish here.

The two routes at a glance

Google’s setup page for website conversions describes two paths once you have chosen a category. Path A uses a Google tag: Google Ads measures the action directly on your site. Path B uses Google Analytics events: you measure the action in Google Analytics 4 (GA4) and bring it into Google Ads. Only key events in Google Analytics can be imported.

Question	Google tag conversion action (Path A)	Imported GA4 key event (Path B)
Where it is defined	In Google Ads, under Goals	In Google Analytics (marked as a key event), then imported
Needs account linking	No, unless you also use Analytics	Yes, Google Ads and Google Analytics must be linked
Needs auto-tagging	Not stated as a requirement on the setup page	Yes, auto-tagging must be on
Default optimisation setting	Chosen when you create it	Secondary by default; change it in Google Ads to use it for bidding
Waiting time	Check the Status column in Goals, Summary	Conversion data can take up to 24 hours to appear in Google Ads after importing a key event
Best when	You want Ads to own the measurement, or need codeless URL-based setup	You already track key events in GA4 and want the same definitions in both tools

Route A: Google tag and a Google Ads conversion action

Step 1: Add a website data source

In Google Ads, open the Goals menu and choose Summary.
Select Create conversion action.
Select Edit data sources for “Conversions on a website”, enter your domain and select Scan.

The scan tells you what happens next. If it finds a Google tag or a linked Analytics property, select Done. If it finds an Analytics property that is not linked, you can turn on the data-sharing switches and select Link. If it finds nothing, use Set up to install a Google tag now or do it later. You need Admin access in Google Ads to do this.

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Step 2: Create the conversion action

Choose the category closest to your goal, then select Create conversion and pick Google tag. Google lists three methods:

Automatically without code: choose an event type and a match rule (URL is, URL contains or URL starts with), then enter the URL of your thank-you page. This is the simplest option, but it does not capture transaction-specific values.
Manually using code: add the snippet with Google tag or Google Tag Manager. Use this for button clicks or dynamic values such as purchase amounts.
Google Tag Manager integration: select Set up in Google Tag Manager, choose a container and add the suggested tags to a workspace, then configure triggers and publish. Google notes that codeless conversions do not support this button.

Step 3: Set the counting and optimisation options

Each action has settings for optimisation, name, value, conversion windows, attribution and enhanced conversions. Two matter most for small accounts. First, mark the action Primary if it should guide bidding, or Secondary (observe only) if you only want to watch it. Second, set the count. Every counts each conversion that follows an ad interaction and suits sales, where each one adds value. One counts a single conversion per ad click and suits leads, where you care that a lead happened, not how many forms one person sent.

Step 4: Check the status

Go to Goals, then Summary, find the action in the Name column and read the Status column in the same row. For troubleshooting a Google tag, Google points to Tag Assistant; for Tag Manager setups it points to its Tag Manager troubleshooting guide.

Route B: Import GA4 key events into Google Ads

This route suits sites that already measure goals in GA4. If you have not defined them yet, see our walkthrough on setting up GA4 key events, and for a fresh property start with how to set up a Google Analytics account.

Step 1: Link the accounts

In Google Analytics, you must be an Administrator or Editor on the property, and you need administrative access in Google Ads. Then:

In Admin, under Product links, click Google Ads links, then Link.
Click Choose Google Ads accounts, select the accounts and click Confirm, then Next.
Review Enable Personalized Advertising, which is on by default, and expand Enable Auto-Tagging to turn auto-tagging on.
Click Next, review, then Submit.

Google Ads data appears in Analytics reports within 48 hours. One side effect: with personalised advertising enabled, Google says events such as add_to_cart, begin_checkout and view_item are also marked as key events, so review your key events list afterwards.

Step 2: Mark the event as a key event

In Google Analytics, go to Admin, then Events under Data display, and use the Mark as key event toggle. A new event may need to fire and show under Recent events first.

Step 3: Import it in Google Ads

Go to Goals, then Summary.
Click Create conversion action and select the Google Analytics property.
Select the event, click Select events, then Save and continue.

Imports start from the moment you create them; historical data from before the import is not included. Imported conversions are Secondary by default, so they will not influence bidding until you change the setting.

Making an action Primary or Secondary

Primary actions appear in the Conversions column and are used for bidding when their goal is used for bidding. Secondary actions are observation only and appear in the All conversions column. To change this, open Summary under the Conversions drop-down in the Goals menu, find the goal containing the action, click Edit goal, choose Primary or Secondary (observe only) in the Conversion action optimization section and click Save. Changes to goal category or optimisation for imported conversions can only be made in Google Ads; edits made in Analytics show only in Change history in Google Ads.

Common mistakes

Double counting

Tracking the same purchase through a Google tag action and an imported GA4 event, with both marked Primary, can inflate results and mislead bidding. Pick one source as Primary for each outcome and leave the other as Secondary for comparison. Google’s setup page also warns to avoid double-tagging if you use a CMS plugin, since this can duplicate conversion reporting.

Wrong counting setting

Using Every for a lead form can count one person several times; using One for a shop can hide repeat purchases. Google recommends Every for sales and One for leads. The setting lives under Goals, Conversions, Summary, then Edit settings and Count, and changes apply only to future reporting, so fix it early.

Missing or incomplete linking

Import only works if the accounts are linked and auto-tagging is on. Google also advises confirming that your site does not alter or drop the click identifier (GCLID), for example through redirects. If imported events stop flowing, verify the link.

Changing goals during learning

Smart Bidding optimises toward your Primary conversion actions, so changing which actions count while a strategy is still learning muddies what it learns. Settle your Primary and Secondary choices before switching on automated bidding; our Smart Bidding guide linked above explains the learning period in detail.

Key takeaways

Create conversion actions in Goals, then Summary, using either a Google tag (Path A) or Google Analytics events (Path B).
Importing GA4 key events needs linked accounts and auto-tagging; imported actions start as Secondary.
Only Primary actions feed the Conversions column and bidding.
Use Every for sales and One for leads.
Check the Status column and use Tag Assistant to troubleshoot a Google tag.

FAQ

Can I use both routes at the same time?

Yes, Google says you can use imported key events alongside Google Ads conversion measurement. Just avoid marking duplicate actions Primary for the same outcome.

Why do my imported conversions not affect bidding?

Conversions created from Google Analytics events are Secondary by default. Change the optimisation to Primary in Google Ads under the goal’s Conversion action optimization section.

How long until imported data shows?

Google states it can take up to 24 hours before conversion data is available in Google Ads after importing a Google Analytics key event. A newly marked key event may also need to fire before it shows up as an import option.

Will past conversions be imported?

No. Google states that historical data from before the import is not included.