By Tihan van der Walt | 13 November 2026
How many leads did the website bring in last month? The GA4 number and the inbox often disagree, sometimes by double, because each form is being counted twice.
Google's help pages say how it should work. On key events: "you can't mark that event as a key event since all pageviews will then count as key events." On testing, Tag Manager's preview mode "allows you to browse a site on which your container code is implemented as if the current container draft was deployed".
GA4 has called conversions "key events" since 2024. Google Ads still calls them conversions.
GA4 is where the data lands and gets reported. Google describes it as a way to "understand the full customer journey, from first visit to purchase." Tag Manager is the installer. In Google's words, "Google Tag Manager lets you configure and deploy tags from Google products and third parties", and you "create one Tag Manager container for each of your company's websites and apps."
Think of GTM as the DB board and GA4 as one of the appliances on it. Put the board in once and you can add, change or remove tracking from a web screen, without a developer opening your theme files each time.
Not always. Google's setup page says "Many CMSs have native integrations with Google Analytics", and if you install by hand you "Paste your Google tag immediately after the <head> on each page of your website." It adds that "Google Analytics tailors the set of default reports based on the information you provide about how you intend to use Analytics."
GTM earns its place when you track WhatsApp, calls and forms, or run ads. Whichever you use, install each tag once.
Account, property, data stream, tag. When you create the property, Google asks you to "select the reporting time zone and currency", and its help page gives a good example of why: "If a visitor comes to your website on a Tuesday in their time zone, but it's Monday in your time zone, the visit is recorded as having occurred on Monday." It also says "Changing the time zone only affects data going forward", and that "If you change the time zone for an existing property, you may see a flat spot or a spike in your data".
Choose South Africa and ZAR, then copy the "G-" tag ID. After that, change data retention from 2 months to 14, filter your office traffic, and link Google Ads and Search Console.
Google's setup page says to "create a Google Tag Manager account that represents the topmost level of organization for your company" and then a container, adding that "You don't need a container for each page of your website." Its preview mode "allows you to browse a site on which your container code is implemented as if the current container draft was deployed", and the debug panel "is not visible to your regular website visitors."
Back up before you paste the snippets, keep one container, and preview before publishing. That's most of it.
The ones that can become money: forms, WhatsApp, calls, email, online orders. Google's key events help puts the limit plainly, saying "you can't mark that event as a key event since all pageviews will then count as key events", and suggests you "modify existing events and create new events from existing events within Google Analytics so you can mark the events as key events without needing to change your website or app setup."
Names I'd use: generate_lead (one of Google's recommended events), click_whatsapp, click_call, click_email and purchase.
Google's own example is a thank-you page: "you want the event to trigger when someone submits their contact information and lands on a confirmation page. You can then mark the event as a key event to see the number of people who successfully submit their contact information." It also warns: "avoid modifying the page_view event since the event will no longer collect pageview data for other pages on your website." And: "Be cautious about overwriting events to avoid unintended consequences."
Track the thank-you page, or a success event from the form plugin, instead of the Submit button.
Tag Manager's help says "a trigger listens to your web page or mobile app for certain types of events like form submissions, button clicks, or page views", that "Every tag must have at least one trigger in order to fire", and that a filter "is made up of a Variable, an Operator, and a Value", where the operator can be "equals, contains, less than, matches RegEx, etc."
Use Click URL with "starts with" tel: for phone taps and "contains" wa.me for WhatsApp.
Link the accounts, then create Google Ads conversions from your key events. Google's page says "the conversion data is shared between Google Ads and Google Analytics so you're viewing the same data across platforms", and that you "must have at least Marketer access to import key events as conversions into Google Ads." One line matters a lot: "Conversion actions that are based on Google Analytics key events or are created through the Google Analytics interface are set to 'secondary' conversion actions to prevent counting the same event twice for bidding."
Worth a look in your own account, because a form counted as primary twice makes every lead seem half price.
Google's enhanced measurement page says "You're required to ensure that no personally identifiable information is collected." Its developer guide adds that "Consent mode allows you to control data collection based on user consent for advertising and analytics purposes", and that "Consent mode was updated in November, 2023 and now contains two additional parameters."
So keep names, emails and phone numbers out of GA4, which also keeps you on the right side of POPIA. Ask a lawyer about the consent banner and privacy policy if you run ad tags.
Tag Manager's preview connects your site "to Tag Assistant so that you can inspect which tags fired and in which order", and "As you click through your previewed website, the debug interface will update information about how your tags are fired." The debug interface "will only appear on the same browser that was used to enable preview mode".
Fill in your own form, tap your own WhatsApp button, and watch. After that, hold GA4 up against the real inbox every month. Add the calls and clicks from your Google Business Profile too, and chatgpt.com referrals, as covered in getting recommended by ChatGPT and Google AI.
GA4's word for a conversion. Google's example is a thank-you page, where you "mark the event as a key event to see the number of people who successfully submit their contact information."
Not for a simple site. Google says "Many CMSs have native integrations with Google Analytics."
A double install is the usual reason, or a form counted on the click.
Google says "You're required to ensure that no personally identifiable information is collected," so no.
Google says conversions "based on Google Analytics key events or are created through the Google Analytics interface are set to 'secondary' conversion actions to prevent counting the same event twice for bidding."
"I'm not going near my website's header" is a perfectly sensible reaction to all of this.
Want your tracking set up properly?
MinuteSteak is one of the big players in South African digital marketing, with about ten years of Google Ads, analytics and website work for clients including Redtech, KMP Media, AAD and Brand South Africa. We set up GA4 and Tag Manager so the numbers match your inbox. Linbro Park, Sandton, by appointment only.
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