How to Set Up GA4 Conversion Tracking: A Key Events Guide

If you can’t see which marketing channel brought a lead, you can’t spend your budget wisely. Google Analytics 4 can tell you exactly that — but only when conversion tracking is set up properly. Out of the box, GA4 records visits, not the actions that make you money.

This guide walks through how I set up conversion tracking for clients: planning, implementation, testing and connecting it to Google Ads.

Key events: GA4’s name for conversions

In 2024 Google renamed conversions in GA4 to key events. A key event is any event you mark as important to your business — a form submission, a purchase, a phone call click. In Google Ads, the actions you optimise for are still called conversions.

Step 1: Decide what to track

Start with the actions that represent real business value:

• Lead forms — contact, quote or booking requests.
• Phone calls — clicks on tel: links, especially on mobile.
• Email clicks — clicks on mailto: links.
• Purchases — for online stores, with revenue values.
• Micro-conversions such as newsletter sign-ups or brochure downloads (track them, but don’t optimise ads for them).

Keep the list short. Five meaningful key events are more useful than thirty noisy ones.

Step 2: Install GA4 correctly

Create a GA4 property and a web data stream, then add the tag to every page — either with the Google tag directly or through Google Tag Manager (GTM). GTM is the better long-term choice when you plan to track several actions or run ads on multiple platforms.

Leave Enhanced measurement switched on. It automatically records page views, scrolls, outbound clicks, file downloads and some form interactions.

Step 3: Track form submissions reliably

Automatic form tracking is not reliable for most contact forms. Better options:

1. Thank-you page: redirect visitors to a dedicated page after submitting, and create a key event when that page is viewed.
2. Custom event: fire an event such as generate_lead when the form is submitted successfully, using GTM or a small piece of code on the site.

Google recommends the event name generate_lead for lead forms, which keeps your data consistent with standard reports.

Step 4: Track phone and email clicks

In GTM, create a trigger for clicks on links whose URL starts with tel: or mailto:, and send an event such as phone_click or email_click to GA4.

Step 5: Mark events as key events

Once the events appear in GA4, open Admin → Events (or Key events) and mark the important ones as key events. Only key events show up in conversion reports and can be imported into Google Ads.

Step 6: Test before you trust the data

• Use Tag Assistant and GA4 DebugView to submit a test form and confirm the event fires once — not twice.
• Check that the event doesn’t fire when the form shows a validation error.
• Look at the Realtime report after publishing changes.

Step 7: Respect privacy and consent

If you have visitors from the European Economic Area, you need a consent banner, and Google requires Consent Mode v2 signals for its advertising features. Configure GA4 and your ad tags to respect visitors’ choices, and mention analytics in your privacy policy.

Step 8: Connect GA4 to Google Ads

Link your GA4 property with Google Ads and import your key events as conversions — or set up native Google Ads conversion tracking, which is usually more accurate for bidding. Make sure each conversion is counted only once across both systems. If you’re new to ads, read the Google Ads mistakes that waste budget — missing tracking is the first one.

Common tracking mistakes

• Counting page views of the contact page as leads.
• Firing the same conversion twice (for example in both GA4 and a plugin).
• Tracking dozens of events and marking all of them as key events.
• Never testing after website changes, so tracking silently breaks.
• Ignoring consent requirements.

Frequently asked questions

Do I need Google Tag Manager?

Not for a basic setup, but it makes tracking easier to manage, test and extend without touching your website code every time.

Why don’t GA4 and Google Ads show the same numbers?

They use different attribution models, time zones and counting rules, and GA4 may model data when visitors decline cookies. Small differences are normal.

How long until data appears?

Realtime and DebugView show events within seconds. Standard reports can take up to a day or two to update.

Want tracking you can actually trust?

I set up GA4, Tag Manager and Google Ads conversion tracking as part of my digital marketing and Google Ads services. Get in touch and find out what your marketing is really delivering.