Why it matters

Google Ads optimizes ads based on conversions. If it does not see them, automated bidding learns from incomplete data and starts buying the wrong clicks. You pay more and get fewer leads.

Reason 1: the form does not send an event

Many modern forms submit without going to a "Thank you" page. A tag set to fire on the thank-you page then sees nothing. The fix is a separate event after a successful submission, for example generate_lead in the dataLayer, with a GTM trigger on exactly that event.

Reason 2: the conversion is in GA4 but not in Google Ads

  • The GA4 event has to be marked as a key event.
  • The GA4 and Google Ads accounts must be linked.
  • The key event must be imported into Google Ads and set as a primary action if the ads should optimize for it.
  • GA4 data reaches Google Ads with a delay, so check the next day.

Reason 3: the cookie banner and Consent Mode

If the banner simply blocks tags until consent, people who decline or ignore it vanish from the statistics completely. Consent Mode v2 tells Google the consent state: when consent is declined, tags do not set cookies, but Google can model part of the conversions. For traffic from the EEA and the UK, Consent Mode is effectively required for ads to work fully.

Reason 4: duplicate and missing tags

  • GA4 is installed both in the code and through GTM, so events are counted twice.
  • The tag is on the home page but missing on new pages or landing pages.
  • The conversion fires on a button click rather than after a successful submission, so even empty attempts are counted.

Reason 5: calls and messengers

Some clients do not fill in the form but tap the phone number or Telegram. Add events for clicks on tel:, t.me, Viber and WhatsApp links. This does not guarantee an inquiry, but it shows interest and helps you see which ads work.

How to check in an hour

  1. Open GTM preview mode and send a test lead.
  2. Check that the event appears in GTM and then in GA4 DebugView.
  3. In Google Ads, check the conversion status and whether it is primary.
  4. Compare the number of leads in your CRM, Telegram or inbox with the number of conversions for a week.
  5. If the gap is large, find the step where the data gets lost.

FAQ

Is it normal for GA4 to show fewer conversions than real leads?

A small gap is normal: ad blockers, declined cookies, different attribution models. If the difference is several times, the setup is the problem.

What are enhanced conversions?

They send hashed form data, such as an email or phone number, so Google can match a conversion to an ad click more accurately. They are turned on after the basic setup.

How much does tracking setup cost?

Setting up GA4 and GTM events costs 4,000 UAH. The exact scope depends on how many forms and contact channels the site has.

Sources