GA4 Conversion Tracking: Set Up Key Events That Count

GA4 Conversion Tracking: Set Up Key Events That Count

GA4 conversion tracking comes down to three jobs: send the right events from your site, flag the ones that matter as key events, and link the property to Google Ads so your bidding can learn from them. Get those three right and you can see which campaigns produce enquiries and sales. Skip any of them and the reports look busy while telling you very little.

I’m Jesse, a senior paid media specialist at Senior Ad Managers. Most of the Australian accounts we audit have GA4 installed. Far fewer have it counting the right things. This guide walks through the setup in order, then shows you how to check it and why the numbers will still differ from your sales records.

TL;DR

• GA4 records events. A conversion is an event you have flagged as a key event, so nothing counts until you mark it.
• Track the action that pays you (a purchase, a booked quote, a qualified call), not every button click.
• Link GA4 to Google Ads, then decide which system owns each conversion action so you never count one lead twice.
• Test every key event before you spend on it, and compare monthly totals against your CRM or sales ledger.
• GA4, Google Ads and your own sales records will never match exactly. A steady, explainable gap is fine. A growing one is a warning.

Table of Contents

• Events, key events and conversions: what GA4 actually calls what
• Decide what deserves to be a key event
• Set up GA4 conversion tracking step by step
• Should you use GA4 or the Google Ads tag?
• How to check GA4 conversion tracking is working
• Why GA4, Google Ads and your sales records show different numbers
• Our view: count the outcome you’d pay a salesperson for
• Get a second pair of eyes on your tracking
• FAQ
• Sources

Events, key events and conversions: what GA4 actually calls what

The naming confuses almost everyone, so start here. In GA4, an event is triggered whenever someone interacts with your site or app: a page view, a scroll, a form submission, a purchase. You then flag the events that contribute to business success as key events, as Google’s own documentation explains. Google used to call these conversions inside Analytics, and many guides and menus still use the old word.

The practical difference is simple:

Without that flag, GA4 treats every action as equal. Semrush makes the same point: unflagged events can’t be separated into trivial clicks and genuine goal completions. That is why a property can hold a year of data and still not answer “how many customers did my ads bring in?”

If you see the phrase “GA4 events vs conversions” in a report, read it as “all recorded actions versus the few that matter”. Your job is to keep the second list short.

Decide what deserves to be a key event

Before you touch a setting, write down the actions that make you money. Be specific to your business model.

Trades and home services. A completed quote request form, a click-to-call that lasts long enough to be a real conversation, a booked job. A pest control or plumbing business rarely benefits from tracking page scrolls or newsletter sign-ups as key events.

eCommerce and DTC. Purchase is the one that matters. GA4 flags the purchase event as a key event automatically, but only when your site actually sends it with the right value and transaction ID. Add to cart and begin checkout are useful as funnel steps and can stay as ordinary events.

Professional services, law and healthcare. Consultation or appointment requests, with the lead form as the main key event. Take care with what you send. Health and legal enquiries can carry sensitive details, so keep names, emails and medical information out of event parameters and URLs, and check the Australian Privacy Principles with your adviser if you’re unsure.

A good rule: if a number moved on this event, would you change your ad budget? If not, leave it as a plain event.

The mistake we see most often

A business flags five or six events as key events “to be safe”: page view of the thank-you page, form start, form submit, phone click and email click. Then Google Ads imports all of them as conversions, and the account reports four conversions for every one real enquiry. Smart Bidding then optimises toward the easiest action, which is usually the cheapest click and the lowest quality lead.

One primary lead action per form or journey is usually enough.

Set up GA4 conversion tracking step by step

This is the order we follow on a new account. It works for a simple WordPress site with a contact form and for a Shopify or WooCommerce store.

1. Install the GA4 tag properly

Use Google Tag Manager or the platform’s native integration, but pick one. Running a plugin and a hard-coded tag together is the quickest way to double-count every event. Confirm there is a single GA4 measurement ID firing per page.

2. Send the event that marks the outcome

There are three common routes:

1. Recommended events with a built-in integration. Shopify, WooCommerce and most booking tools can send purchase or generate_lead for you.
2. A thank-you page. Fire an event only when the confirmation page loads after a successful submission. This is the simplest option for a form that redirects.
3. A form submit trigger in Tag Manager. Use this when the form doesn’t redirect. Test it carefully, because a trigger that fires on click rather than on success will count failed submissions too.

Use Google’s recommended event names where they exist (generate_lead, purchase, sign_up) so reports and Google Ads recognise them. Pass a value and currency where you have one. For an Australian business, that currency is AUD, and it should be consistent everywhere.

3. Flag the event as a key event

In your GA4 property, go to Admin, then Events, and mark the event as a key event. Google notes that events must have occurred before they appear in the list, so submit a test enquiry first. For purchase, the flag is applied for you.

4. Link GA4 to Google Ads

Linking a GA4 property to Google Ads lets the two systems share key event data and audiences, and allows Smart Bidding to optimise on GA4 conversion actions. In Google Ads, you then import the key event as a conversion action.

One detail catches people out. Settings such as Action Optimization can’t be changed from inside Google Analytics. They live in Google Ads. Google also says that managing most conversion settings in both interfaces helps keep data consistent, so when someone changes a setting in one, make sure the other is checked.

5. Choose a single owner for each conversion

You can measure a form submission with the Google Ads tag, with a GA4 import, or both. If both are set to count and both are set as primary, you inflate results. Pick one as the primary action for bidding and mark the other as secondary, or don’t import it at all. We cover the Google Ads side in more depth in our guide to Google Ads conversion tracking.

6. Set the attribution you want

For web conversions shared with Google Ads, Google lets you choose between Google paid channels, or paid and organic channels. Changes apply to conversions moving forward, not to history. Make the choice once, write it down, and don’t flip it mid-month, or you will compare two different measures.

If you want to understand how credit gets split between touchpoints before you change budgets, this piece on GA4 attribution across touchpoints is worth a read.

Should you use GA4 or the Google Ads tag?

The question comes up in almost every first call. Our honest answer depends on what you need.

• The Google Ads conversion tag counts conversions after an interaction with your ads. It’s closest to the click and generally the more direct signal for bidding.
• GA4 imports give you one set of definitions across all channels, so you can compare Google Ads against email, organic and direct in the same place.

Many accounts run the Google Ads tag as the primary action and keep GA4 for cross-channel analysis. Others import GA4 key events and use them for bidding because the setup is already clean. Either can work. What doesn’t work is feeding both into bidding without deciding which one counts.

Whichever you pick, the real test is downstream: do the leads turn into paying customers? Bidding on a form fill is an approximation. If you want bidding to learn from closed sales, that’s where offline conversion tracking comes in, which feeds sales from your CRM back to Google Ads.

How to check GA4 conversion tracking is working

Installed and working are different things. Run these checks before you put real budget behind a campaign.

1. Submit a test enquiry or buy a test product. Use a real browser on a normal connection, not only the preview mode of your tag manager.
2. Watch it arrive. GA4’s Realtime report and DebugView show events as they are received. You should see your event name, the right parameters and one hit, not two.
3. Check the key event column. In the Events report, the event should show as a key event. If the event count is positive but the key event count is zero, the event is firing and the flag is missing.
4. Check the value. For purchases, compare the value in GA4 to the order total, including whether GST is in or out. Pick one treatment and stay with it.
5. Check Google Ads. Open the conversion actions page and confirm the status. A conversion action that shows as inactive or without recent conversions needs attention before you scale.
6. Test from an ad click. Click a test ad or add gclid to your landing page URL, and confirm the session is credited to Google Ads. If paid traffic lands in “direct” or “unassigned”, look at auto-tagging and your redirects.
7. Test the forms people actually use. Mobile, Safari and a consent-banner decline all behave differently.

For a longer list, our GA4 audit checklist goes through twelve checks before you trust the data. If your store is the concern, see our guide on GA4 ecommerce tracking.

Why GA4, Google Ads and your sales records show different numbers

This is the question that makes owners distrust the whole setup. A mismatch isn’t automatically a fault. The systems count by different rules.

Google Ads only counts conversions that follow an interaction with an ad from that account. GA4 measures the whole website across every channel, within the limits of consent. Beyond that, the usual causes are:

• Different attribution settings. One system credits the last click, another uses a data-driven model, and a conversion may land on a different date.
• Consent and blockers. Visitors who decline cookies or use blockers may not be measured in the same way across tools.
• Double firing. A thank-you page that reloads, or a plugin and Tag Manager both sending the event, creates duplicates.
• Conversions that are not sales. A form fill is not a customer. Some leads are spam, wrong numbers or people outside your service area.
• Brand searches. If someone searches your business name and clicks your ad, Google counts a conversion even though you would likely have won that customer anyway. This is the gap behind a real estate agency we worked with: reported cost per new client was $300 and the true cost was $800, because most conversions were people searching the agency’s name. After the fix it reached $68 within about three months and held for 10 months.

A gap of 10 to 20 per cent between platforms is common and not worth chasing. What you want is stability. If GA4 says 80 leads, Google Ads says 95 and your CRM holds 60 qualified ones every month, you have a model you can reason with. If the gap swings from 10 per cent one month to 50 per cent the next, something is broken.

A simple monthly reconciliation

Once a month, put three numbers side by side for the same dates and the same campaigns: conversions in Google Ads, key events in GA4, and enquiries or sales recorded in your CRM or accounting system. Write the ratios down. Then ask why for any month that moves. It takes about 30 minutes and tells you more than most dashboards.

Our view: count the outcome you’d pay a salesperson for

We run Google Ads and Meta Ads for Australian businesses, from trades to eCommerce brands, and tracking is the first thing we repair on a new account. Here’s what we’ve learned.

Platform numbers tell a good story. The gap between that story and your bank account is where wasted spend hides. A pest control company came to us with a cost per lead of $700. We fixed tracking so we captured GCLID and keyword data, added weekly negative keywords to remove DIY and product searches, raised the budget from $50 to $100 a day and moved from Maximize Clicks to Maximize Conversions. Cost per lead dropped to $100 in about six weeks. Tracking made the rest visible. It didn’t make the improvements on its own.

We also keep match types tight. For small and mid-sized Australian accounts we use exact and phrase match with tight negatives and review search terms weekly. Broad match hands your budget to a model that has not yet learned what a good lead looks like, and with a few thousand dollars a month there’s no room for that experiment. A plumber we moved off broad match keywords now gets around $3 to $4 back for every dollar spent, checked in his CRM.

So our advice on GA4 is practical. Track one primary outcome per journey. Keep the others as plain events. Check the totals against what landed in your CRM. Results can’t be guaranteed, but a clean measurement base lets you see what’s working and cut what isn’t.

— Jesse Lees

Get a second pair of eyes on your tracking

If you’re not sure whether your key events, Google Ads imports and CRM numbers line up, the quickest route is an audit. Our $99 AUD Google Ads audit reviews your conversion actions, search terms and account structure, and tells you where spend is leaking. If you want us to run the account afterwards, Google Ads management starts at $1,725 AUD a month per platform, with no setup fee, no percentage of ad spend and a 3 month minimum.

If your site needs the tracking itself rebuilt, our website tracking service covers GA4, Tag Manager and CRM connections.

FAQ

What is the difference between a GA4 event and a conversion?

An event is any interaction GA4 records, such as a page view or a form submission. You flag the events that matter to your business as key events, and Google Ads can import them as conversions. Think of events as the raw data and key events as the shortlist.

How many key events should I set up?

As few as your business needs, often one primary action per journey. A trade business might have a quote form and qualified calls. An online store usually needs purchase. Extra key events can pull Google Ads bidding towards cheap actions that don’t pay.

Do I need Google Tag Manager for GA4 conversion tracking?

Not always. Many platforms send purchase or lead events through a built-in integration, and a thank-you page can trigger an event directly. Tag Manager helps when you have forms without a confirmation page, need custom parameters or want to manage several tags in one place. Avoid running Tag Manager and a plugin together for the same event.

Why does Google Ads show more conversions than GA4?

Usually because of different attribution rules, conversion dates or counting settings, or because the same action is counted by two tags. Check which action is primary and whether the GA4 import and the Google Ads tag are both feeding bidding. Then compare both to your CRM to see which one sits closer to actual customers.

Can GA4 track phone calls?

GA4 can record a click on a phone number as an event, but it can’t tell you whether anyone answered or whether the call became a job. For call-driven businesses, add call tracking and judge calls by length and outcome. Our call tracking setup guide covers the Australian details.

Sources

• Conversions and key events in Google Analytics 4
• Google Analytics migration reference: linking GA4 to Google Ads
• Create Google Ads conversions based on Google Analytics key events
• Measure web key events from Google Analytics properties
• Google Analytics for beginners: the complete GA4 guide
• GA4 attribution across touchpoints

Recommended

• GA4 Ecommerce Tracking: Reconcile CRM Before Scaling Ads in Australia
• GA4 Audit Checklist: 12 Checks Before You Trust the Data
• Conversion Tracking & Analytics Setup (GA4, GTM)