To set up Google Analytics 4, create a GA4 property with a web data stream, install the Google tag on your site (we recommend doing it through Google Tag Manager), and then configure the settings most people skip: consent mode, key events, data retention, internal-traffic filters and links to Google Ads, Search Console and BigQuery. The install takes minutes. The configuration is what decides whether you can trust the numbers a year from now.
This checklist covers all of it in order, for 2026. Universal Analytics stopped processing data in July 2023, so GA4 is the only Google Analytics there is; if you’re inheriting an old setup, the “common mistakes” section at the end is where to start.
What should you decide before you set up GA4?
Ten minutes of planning saves a rebuild later:
- What counts as success? A purchase, a demo request, a trial sign-up, a qualified lead. These become your key events.
- Which sites and apps belong together? One property per business is usual; several domains that share a user journey (a site plus a separate checkout or app) should share a property with cross-domain tracking.
- Who owns the accounts? The GA4 account and the GTM container should sit under your company’s Google account, with agencies and freelancers given access, not the other way round.
- Naming conventions. Decide how events and parameters are named (GA4 uses lowercase with underscores, such as
generate_lead) and stick to it. Inconsistent names are one of the most common reasons GA4 reports become unreadable.
How do you create a GA4 account and property?
- Go to Google Analytics and click Start measuring (or Admin → Create → Account if you already have one).
- Name the account, usually after your company.
- Create a property: give it a name and set the reporting time zone and currency you report in. These affect how days and revenue are counted, so get them right now.
- Describe your business (industry and size) and choose your business objectives. These only change which default reports you see.
- Choose Web as the platform, enter your site URL and name the stream. Leave enhanced measurement on: it tracks page views, scrolls, outbound clicks, site search, video engagement, file downloads and form interactions without extra code.
- Copy the Measurement ID (it starts with
G-). You’ll need it in the next step.
How do you install GA4 with Google Tag Manager?
Google Tag Manager isn’t required, but we recommend it: your GA4 events, ad platform tags and consent setup live in one place, with preview testing and version history. If you’re new to GTM, our Google Tag Manager service page explains what it does.
- In GTM, open your container and go to Tags → New.
- Choose the Google Tag tag type. (Older guides, including the earlier version of this one, mention a “GA4 Configuration” tag; Google replaced it with the Google tag in 2023.)
- Paste your Measurement ID as the Tag ID.
- Set the trigger to Initialization – All Pages, so the tag loads before other tags on every page.
- Name the tag clearly (for example “Google tag – GA4”), then use Preview to check it fires, and Submit to publish the container.
For actions enhanced measurement doesn’t cover, such as a demo request or a sign-up, add Google Analytics: GA4 Event tags with their own triggers and parameters. Our GA4 event tracking guide walks through that.
Without GTM: in GA4 go to Admin → Data streams → your web stream → View tag instructions → Install manually, copy the gtag.js snippet and paste it into the <head> of every page (usually your site’s global header). Most CMS and shop platforms also have a field or plugin for the Measurement ID. It works, but every new event then needs a developer.
Which GA4 settings should you configure straight after installing?
This is the part of the checklist most setups skip.
| Setting | Where | What to do |
|---|---|---|
| Consent mode v2 | Your consent banner (CMP) and GTM | Set consent defaults before any tag fires, and pass users’ choices to Google tags. Required for EEA traffic if you use Google Ads audiences or measurement. |
| Data retention | Admin → Data collection and modification → Data retention | Change from the default 2 months to 14 months, the maximum for standard properties. It limits how far back explorations can go. |
| Internal traffic | Admin → Data streams → Configure tag settings → Define internal traffic, then Admin → Data filters | Add your office IPs, then switch the internal-traffic filter from Testing to Active. |
| Unwanted referrals | Configure tag settings → List unwanted referrals | Add payment providers, booking tools and embedded-form domains so they don’t steal credit for conversions. |
| Cross-domain tracking | Configure tag settings → Configure your domains | List every domain in the same user journey. |
| Key events | Admin → Events (or Key events) | Mark only the events that create value. GA4 renamed “conversions” to “key events” in 2024. |
| Custom dimensions | Admin → Custom definitions | Register any event parameter you want to report on; unregistered parameters don’t appear in reports. |
| User-ID | Your site’s data layer and the Google tag | If people log in, send a stable internal user ID so GA4 can join their devices. |
Which products should you link to GA4?
- Google Ads: import key events as conversions and share audiences. Without this link, Google Ads bids on its own tag’s data only.
- Search Console: brings organic queries and landing pages into GA4.
- BigQuery: sends raw, event-level data to Google’s data warehouse every day. It’s the only way to keep full history beyond the retention limit and to join GA4 with CRM or product data. Switch it on early, because the export only starts from the day you link it. BigQuery is billed by Google separately, so check the expected volume first. Our GA4 and BigQuery guide goes further.
Google signals is optional; turn it on only if your privacy policy and consent setup cover it.
How do you check that GA4 is working?
- Test before you publish: GTM Preview (Tag Assistant) shows which tags fire on each page, and GA4’s DebugView shows the events arriving with their parameters.
- Check Realtime after publishing: your own visit should appear within a minute or two.
- Wait a week, then review. Look for:
- your own domain, payment providers or booking tools in the referral traffic;
- unusually high Direct traffic, which often means broken cross-domain tracking or redirects stripping UTM parameters;
- “(not set)” landing pages, which usually means events arriving without a page view in the same session;
- key event counts that don’t match your CRM or shop;
- sudden jumps or drops by device, browser or landing page that nothing explains.
- Write changes down. Note tracking and site changes with the date (GA4 supports annotations on the timeline, or keep a shared changelog). Six months later it’s the only way to explain a step change in the data.
What are the most common GA4 setup mistakes?
In audits we see the same handful again and again:
- Data retention left at 2 months, so year-on-year explorations are impossible.
- The tag installed twice (in the theme and again in GTM), doubling page views and events.
- Too many key events, such as scrolls or newsletter sign-ups, so Google Ads optimises for cheap actions instead of revenue.
- No internal-traffic filter, so your team’s own visits inflate engagement and conversions.
- Consent mode missing or misconfigured, so data from consenting EEA visitors is lost or ad features stop working.
- E-commerce values that don’t reconcile with the shop, usually because of missing transaction IDs or purchase events firing on page reload.
- Nobody tests after site changes. A redesign or new checkout silently breaks triggers. Recheck key events after every release.
Fixing these is often the quickest win in analytics. For Hemptouch, analytics fixes and a blog redesign took the conversion rate from 0.5% to 2% in six months, partly because the team could finally see where visitors dropped off.
FAQ
Do I need Google Tag Manager to set up GA4?
No. You can paste the gtag.js snippet into your site’s header. GTM is still the better choice for most businesses, because every later event, ad platform tag and consent rule can be added without changing site code.
How long does it take for data to appear in GA4?
Realtime and DebugView show data within minutes. Standard reports can take up to a day or two to process, so don’t judge the setup on the first afternoon.
Can I move my old Universal Analytics data into GA4?
No. Universal Analytics stopped processing data in 2023 and its interface and API have since been shut down. GA4 starts from the day you install it, which is another reason to set retention and the BigQuery export up on day one.
Should I set up GA4 myself or hire someone?
A basic install is a reasonable DIY job. Consent mode, cross-domain tracking, e-commerce and a reliable key-event setup are where most self-built properties go wrong. Our guide to what a GA4 consultant does covers when outside help pays off, and our GA4 consulting service covers audits and setups.
If you’d like a second pair of eyes on your setup, get in touch.
