Google Analytics 4 (GA4 for short) is Google's free analytics tool for measuring a site's visitors and how they behave. It replaced the old Universal Analytics and does not work the same way: everything is now built on the event, not the "session." In this article I'll walk you through creating a GA4 property from scratch, adding the measurement code to your site, sending your own events, and reading the right report once you open the dashboard.
Creating a property and getting your Measurement ID
The first step is to create an account and a property inside it at analytics.google.com. A property is the data container that represents a single website (or app). The setup wizard walks you through, in order: account name → property name and time zone → business details → choosing a data stream. For a website you pick the "Web" stream and enter your site's address.
When the stream is created you get a Measurement ID that starts with G-, for example G-XXXXXXXXXX. This is the key that connects your site's data to GA4. On the same screen, Enhanced measurement is on by default; leave it on, because it automatically collects events such as page views, scrolls, outbound link clicks, site search, file downloads and video engagement.
Adding the measurement code to your site
There are two common methods: the gtag.js tag directly, or Google Tag Manager (GTM). For a single site with simple needs, the direct tag is fastest. Add the snippet you're given to the <head> of every page, as high up as possible:
<script async src="https://www.googletagmanager.com/gtag/js?id=G-XXXXXXXXXX"></script>
<script>
window.dataLayer = window.dataLayer || [];
function gtag(){dataLayer.push(arguments);}
gtag('js', new Date());
gtag('config', 'G-XXXXXXXXXX');
</script>Replace G-XXXXXXXXXX with your own ID. The moment the gtag('config', ...) line runs, a page_view event is sent automatically; you don't need to do anything extra. If you run several sites or want to manage marketing tags without writing code, prefer GTM: you then place only the GTM container snippet on the page and configure the GA4 tag from the Tag Manager interface.
Verifying the setup works
To confirm data is being collected, use two tools. The first is the dashboard's Realtime report: open your site in a new tab and within a few seconds you should see yourself as an active user. The second is DebugView: when you connect the browser in debug mode using Google's official Tag Assistant, you can watch every event live, one by one, with its parameters. Whenever you define a new event, always verify it in DebugView before going live.
The first data usually takes 24–48 hours to flow into the standard reports, so it's normal for most of the dashboard to look empty on day one. The Realtime report, however, works instantly and is the most reliable signal for a setup check.
Event tracking: the heart of GA4
In GA4 every interaction you measure is an event. Events fall into four groups:
- Automatically collected events — such as
first_visitandsession_start; gathered without you doing anything. - Enhanced measurement events — such as
scroll,click(outbound) andfile_download; collected automatically when the setting is on. - Recommended events — names Google standardizes for things like e-commerce or sign-ups (for example
sign_up,purchase). - Custom events — site-specific events you define yourself.
To send your own event you use gtag('event', ...). For example, to measure clicks on a "Contact" button:
document.querySelector('#contact-btn')
.addEventListener('click', function () {
gtag('event', 'contact_click', {
method: 'button',
page: location.pathname
});
});The second argument is the event name, the third is whatever parameters you want. Write names in lowercase with underscores (contact_click) and stay consistent, because GA4 groups event names exactly. If you treat an event as an important conversion, mark it as a key event under Admin > Events / Key events; it will then be reported as a conversion metric.
Reading the core reports
The Reports section in the left menu is organized around the visitor's life cycle. In practice you'll look at these metrics most:
- Users — the number of unique people who entered the site.
- Sessions — the number of visits; one user can start several sessions.
- Engagement rate — the share of sessions that lasted 10+ seconds, produced a conversion, or had at least two page views. In GA4 this replaces the old "bounce rate."
- Event count and key events — total interactions and the ones that turn into conversions.
Two reports cover most daily work. The Acquisition report shows where traffic comes from: organic search, direct, social, referral. Here, using the "first user source / medium" dimension, you isolate the channel that first brought a visitor to the site. The Engagement > Pages and screens report tells you which URLs are viewed most and which content genuinely draws interest. A channel that brings lots of traffic but produces low engagement is a sign of poor-quality source.
When the standard reports feel too narrow, use Explorations. There you build free-form tables, drag dimensions and metrics, and create your own cross-analysis (for example conversions by country, or engagement time by landing page).
Common setup mistakes
- Placing the code in the wrong spot — if you bury the tag at the end of
<body>, some page views can be missed; keep it high inside<head>. - Not filtering your own traffic — under Admin > Data settings > Data filters, flag internal (developer) traffic so your own visits don't inflate the data.
- Inconsistent event names —
ContactClickandcontact_clickare two different events to GA4; decide on a naming standard from the start. - Skipping consent management — measuring EU visitors without cookie consent creates legal risk; load GA4 conditionally behind a consent banner.
Frequently Asked Questions
What's the difference between GA4 and Universal Analytics?
Universal Analytics was focused on sessions and page views; GA4 is fully event-based, meaning every interaction including a page view is measured as an event. This makes it easier to unify web and app data in one model and to track custom interactions with little or no code.
Is GA4 the same as Search Console?
No. Search Console measures search behavior before a user enters the site (impressions, queries, ranking); GA4 measures behavior after a user is on the site (sessions, events, conversions). Reading the two together shows both how you're found and what people do.
Why doesn't my data show up in the dashboard immediately?
The Realtime report works instantly, but the standard reports usually take 24–48 hours to fill in. If you want to verify the setup right away, use Realtime and DebugView, then check the detailed reports the next day.
Want to be sure your GA4 setup produces correct data? For event-tracking design, key-event configuration and reading reports correctly, get in touch with me — let's build your measurement layer and turn your data into growth decisions.