GA4 Conversion Tracking for a Landing Page: Setup

Why analytics has to be live before the first ad dollar

A landing page without conversion tracking turns ad spend into a guess: the ad platform shows clicks, but not which keyword, ad, or campaign produced a lead, or what a lead cost. And you cannot collect it later. Google Analytics 4 starts recording the day the tag goes live and never fills in the past.

Take a meal-prep delivery in Austin spending $1,500 a month on Google Ads for "meal prep delivery austin." At, say, $2.40 per click, that is about 620 clicks a month; if 3% submit the order form, that is 18 leads at roughly $83 each. Without tracking the owner sees 620 clicks and a handful of orders that "probably came from the ads." With tracking she sees one ad group producing 14 of the 18 leads at $50 each and the other producing 4 at $200. That is the difference between a campaign you can improve and one you can only pay for.

Set up GA4 on a landing page: property, Measurement ID, first check

Create a GA4 property

Sign in to Google Analytics with the account that should own the data: the business account, not a freelancer's personal one. Open Admin (the gear icon at the bottom left), click Create, then Property, enter the business name, time zone, and currency, answer the questions about the business, and click Create. Google's walkthrough is in Set up Analytics for a website.

GA4 then asks for a platform: pick Web, enter the landing page URL and a stream name, and click Create stream; the value you need is at the top right of the stream screen that opens.

Find the Measurement ID (G-…)

The Measurement ID is G- followed by ten letters and digits, for example G-1A2B3C4D5E; it identifies your web data stream, and every hit from the page carries it. Later it is always available under Admin, then Data streams, then your stream.

Put the ID on the page

Builders take the ID and add the tag themselves. In Pageo, open the site settings, go to the Analytics tab, paste the Measurement ID into the Google Analytics field, and save; the field expects only the ID, since the tracking code is added for you. Then publish the site, or click "Update site" if it is already live, because changes reach visitors only after a new publication, and press "Check connection" in the same tab: it looks for the tag on the published page. The analytics and goals guide covers the other counters.

Verify with the Realtime report

Open the published page in a private browser window, then in GA4 go to Reports, then Realtime. Within a minute you should see one active user and a page_view event. If nothing appears after two minutes, suspect an ad blocker in the test browser, a page not republished after the ID was saved, or a typo in the ID. Do not move on until Realtime shows you.

Key events: how GA4 counts conversions now

GA4 records everything as events, from page_view and scroll to form_submit and whatever your builder sends. A key event is an event you have flagged as one that matters for the business. Until 2024 GA4 called these "conversions"; Google renamed them to key events so that "conversions" would mean only the actions shared with Google Ads and used for bidding. Google's reference is in Key events.

Marking an event as key gives it its own report, lets you import it into Google Ads as a conversion action, and adds it as a column in acquisition reports, so you can see which channel produced it. For a landing page one key event is enough: the lead.

Track form submissions in GA4: which key event to use

Three ways catch a lead in GA4; they differ in how much can go wrong.

Option 1: a thank-you page view marked as a key event

The form redirects to /thank-you, GA4 records a page_view for that URL, and you flag that page view as the key event. Step by step:

1. Create a short thank-you page at /thank-you: "Thanks, we will call you within an hour," plus what to do meanwhile.
2. Point the form at it. In Pageo: site settings, then Delivery, then the "Thank-you page" row; enter /thank-you and save (forms and the thank-you page). An empty field leaves the visitor on the page with a message: GA4 gets no page view to count; the builder's own generate_lead event from option 3 still fires.
3. Exclude the page from search, or visitors who never filled out a form will count as leads: switch off "Show in search" for that page in the indexing settings.
4. In GA4, open Admin, then Data display, then Events, and click Create event. Name it lead_thank_you and add two conditions: event_name equals page_view, and page_location contains /thank-you. Save.
5. Open Admin, then Key events, click New key event, type lead_thank_you, and save. This works before the event has ever fired.
6. Set the counting method to "once per session" from the key event's menu, or a visitor who refreshes the thank-you page counts twice.
7. Publish, submit the form with "Test" in the name, and watch Realtime: page_view for /thank-you, then lead_thank_you in the key events card. The test lead should also arrive through the connected delivery channel.

Option 2: enhanced measurement form interactions

Enhanced measurement is on by default in every web data stream, and its "Form interactions" option sends form_start when a visitor begins typing and form_submit when the browser submits a form; you can mark form_submit as a key event and skip the thank-you page (Enhanced event measurement).

The catch is in the word "browser." The event fires when the form is sent, not when the lead is accepted, so a submission rejected for a bad phone number can still count; it fires for every form on the page, including a newsletter box in the footer; and depending on how a builder sends the form, it may not fire at all.

Option 3: the event your builder sends

Some builders send a dedicated event on a successful submission. Pageo sends generate_lead, one of Google's recommended event names, on every form submission; mark it as a key event and it counts leads without a redirect. Do not also mark the thank-you page view, or every lead counts twice.

The page view is the most robust of the three on a builder site: it does not depend on the builder's script or on how the form is wired, and if you move to another platform next year, the key event survives the move.

Five GA4 reports a landing page owner should read

GA4 has dozens of reports; a landing page needs five. If your left menu looks different, type the report name into the search box at the top of GA4.

Realtime (Reports, then Realtime). The live check from the setup above: use it on launch day and after every change to the page or the tag, not as a daily report.

Traffic acquisition (Reports, then Acquisition, then Traffic acquisition). Sessions by channel: Paid Search, Organic Search, Direct, Paid Social, Email. Switch the dimension to "Session source / medium" or "Session campaign" for individual campaigns, and read the key events column, not sessions. For the meal-prep example this is where "Paid Search: 540 sessions, 16 key events" sits next to "Paid Social: 700 sessions, 2 key events."

Key events (Reports, then Engagement, then Key events). The count of lead_thank_you by day, the number to compare with the leads in your inbox or CRM. A gap of a few percent is normal, since ad blockers and declined cookie consent hide some visitors; a gap of half means the key event is misconfigured.

Landing page (Reports, then Engagement, then Landing page). Sessions and key events per entry page. With more than one landing page, this is where you compare them: the corporate-lunch page at 4.1% against the family-plan page at 1.9%.

Pages and screens (Reports, then Engagement, then Pages and screens). Views per page. On a one-page site its job is to confirm that /thank-you gets views only after submissions; more views than leads means somebody found it through a link or a search result.

Link GA4 to Google Ads and import conversions

Linking turns the key event into a Google Ads conversion: Google Ads then reports cost per conversion for each keyword and ad, and Smart Bidding strategies such as Maximize conversions optimize toward leads instead of clicks.

1. In GA4 open Admin, then Product links, then Google Ads links, click Link, choose the Google Ads account, and submit. You need the Editor role in GA4 and admin access to Google Ads; the steps are in Link Google Ads and Analytics.
2. In Google Ads open Goals, then Conversions, then Summary. Click New conversion action, choose Import, then Google Analytics 4 properties, then Web, pick lead_thank_you, and import it.
3. Set the imported action as Primary so bidding uses it, and make sure no second conversion action, such as a Google Ads tag on the same thank-you page, counts the same lead; two actions for one lead double the reported conversions.
4. Wait a day, then compare. The two tools will not match exactly, because Google Ads dates a conversion by the click and uses its own attribution, while GA4 dates it by the event; in our experience a gap of up to roughly a fifth is normal, while one tool showing double the other is a bug.

Give the campaign two to four weeks and a couple of dozen conversions before judging it; bidding strategies need data.

UTM parameters: know which ad brought the lead

Google Ads with auto-tagging on tells GA4 everything about the click by itself. Every other source needs UTM parameters, text added to the link: utm_source (where the link lives: facebook, newsletter), utm_medium (the type: cpc, email, social), utm_campaign (the offer: spring_family_plan), and optionally utm_content to tell two ads apart and utm_term for a keyword. A link for a Meta ad looks like https://example.com/?utm_source=facebook&utm_medium=cpc&utm_campaign=spring_family_plan&utm_content=video_a.

Three rules keep the data usable: lowercase everywhere, because Facebook and facebook become two rows in GA4; one written convention for source and medium, since Google's Campaign URL Builder assembles the link but does not stop you from inventing a new medium each time; and no UTMs on links inside your own site, because a home-page button with utm_source=homepage overwrites the real source of the visit.

GA4 shows UTM data in Traffic acquisition under Session source / medium and Session campaign. A builder's lead list can add what GA4 cannot: Pageo, for example, shows the UTM tags of the visit next to each lead, or "Direct" when there were none (leads).

Typical GA4 conversion tracking mistakes

Two tags on one page. A tag added through the builder's settings and again through Google Tag Manager or a pasted snippet sends every event twice; the symptom is a key event count exactly double the leads. Check how many times the Measurement ID appears in the page source.

The key event never fires. The usual causes, in order: the site was not republished after the setup; the form does not redirect to the thank-you page; the page_location condition has a typo or misses a trailing slash; an ad blocker in the test browser.

Reading sessions instead of key events. A channel with 700 sessions and 2 leads is worse than one with 200 sessions and 9 leads. Sort every acquisition report by the key events column.

No UTMs on ads outside Google. Meta, TikTok, LinkedIn, email, and a QR code on flyers all land in "Direct" or "Referral" without UTMs, and the report cannot tell which of them paid off.

If the form itself is losing leads, the fix is on the page, not in analytics: see lead form best practices.

FAQ

Is GA4 free for a small business site?

Yes. Standard Google Analytics 4 is free, with no traffic limit a landing page will ever reach; the paid Analytics 360 exists for large companies. What costs something is the time to set it up correctly.

Do I need Google Tag Manager to track form submissions in GA4?

Not for a landing page on a builder. A thank-you page key event needs only the Measurement ID on the site and a redirect after the form, and a builder's own event such as generate_lead needs even less. Tag Manager earns its place when you have many tags, several conversions, or a developer to maintain it.

Can I still use my old Universal Analytics property?

No. Universal Analytics properties stopped processing new data in 2023, and their reports were removed later. If a builder or plugin asks for a UA- ID, replace it with a GA4 Measurement ID that starts with G-.

How long until conversions show up in GA4 and Google Ads?

Realtime shows the event within a minute of the test submission. Standard GA4 reports fill in over the following day or two, and an imported conversion in Google Ads can take another day. If nothing appears in Realtime, the problem is in the setup, not in the delay.

Key takeaways

• Put the GA4 tag on the landing page before the first ad runs; GA4 never fills in the past.
• The Measurement ID starts with G-; a builder adds the tag from the ID alone. Confirm in Realtime before anything else.
• Conversions in GA4 have been called key events since 2024. A landing page needs one: the lead.
• The most robust lead event on a builder site is a thank-you page view, counted once per session and hidden from search.
• Read Traffic acquisition, Key events, and Landing page by the key events column, not by sessions.
• Link GA4 to Google Ads, import the key event as a Primary conversion, and add UTMs to every non-Google link.