Google Ads for eshops: how to track conversions correctly, so you see sales, not clicks.

A conversion, in Google Ads, is the action you define as a result; for an eshop, the order. Google Ads counts how many conversions each campaign brought, and it learns from them.

The second part is the important one. Automated bidding strategies, which most Shopping and Performance Max campaigns use today, bid higher on searches that look like the ones that brought conversions. If the conversion is wrong, the campaign learns the mistake and spends more on it.

In Google Ads, every conversion is either primary or secondary. Primary conversions count in the “Conversions” column and steer bidding; secondary ones appear only in the “All conversions” column, for you to keep an eye on. On an eshop, the only primary conversion should be the purchase.

In GA4 (Google Analytics), the important actions are now called key events. A key event becomes a conversion for Google Ads only when you link it to your Google Ads account.

Six common mistakes make Google Ads show more purchases or different values from your eshop. Most are quick to fix; the hard part is spotting them.

Mistake	What you see	The fix
“Add to cart” is a primary conversion	Many conversions, few orders	Only the purchase as primary; the cart as secondary
The thank-you page counts every time it opens	The same purchase counts two or three times	The order number (transaction ID) on every purchase
The purchase counts both from GA4 and from the Google Ads tag	Double purchases in the “Conversions” column	Only one as primary, the other secondary
The same value on every purchase, or none	You don’t know which campaign brings the big baskets	The real value of each order
The bank’s payment page shows up as a source	In GA4, purchases “come from” the bank	The bank’s domain in GA4’s unwanted referrals
Tags load before the choice on the banner	Tracking without consent	Banner and Consent Mode v2 before any tag

The second mistake is the most common. The customer reloads the thank-you page, or opens it again from the confirmation email, and the tag sends the purchase again. When every purchase carries the order number, Google Ads recognises the second one as a duplicate and doesn’t count it.

The fifth hides well. When the customer pays on the bank’s page and comes back to the eshop, GA4 sees a new visit from the bank. If you add the bank’s domain to the unwanted referrals list, the purchase goes to the right source.

The last one isn’t only a tracking issue: it’s a legal obligation, and we come to it below.

Google Ads doesn’t only count how many purchases were made, but also what each one was worth. With the value, a campaign can chase revenue and not just the number of orders, with strategies such as “Maximize conversion value” and “Target ROAS”.

Decide once what “value” means for you, and write it down: with or without VAT, with or without shipping, before or after discounts. We usually recommend the value of the products without VAT and shipping, because that’s your real revenue. Whatever you choose, keep it the same in GA4, in Google Ads and in your business software’s reports.

If your margin varies a lot from one category to another, the value can come from the profit. That needs a connection to your business software, because the purchase cost must never be visible in the browser. It’s one of the reasons server-side tracking is worth it.

In Greece, advertising cookies and Google Analytics may be used only with the visitor’s consent. The recommendations 1/2020 of the Hellenic Data Protection Authority, the Greek DPA (25 February 2020), also ask for:

• No pre-ticked choices: pre-ticked boxes, carrying on browsing and scrolling are not consent.
• Nothing before the choice: until the visitor has chosen, no tag that isn’t strictly necessary loads.
• “Reject” as easy as “Accept”: at the same level, with the same number of clicks, and with buttons of the same size and colour.
• No cookie wall: anyone who says no still gets into the site as normal.

Google, for its part, requires advertisers to collect consent from users in the European Economic Area and to pass it on. Since March 2024 this is done with Consent Mode v2, which tells Google’s tags what the visitor chose, through four settings:

Setting	What it allows	If the visitor says no
ad_storage	Advertising cookies	No Google Ads cookies are written or read
analytics_storage	Google Analytics cookies	GA4 writes no cookies; at most it sends cookieless pings
ad_user_data	Sending user data to Google for advertising	Enhanced conversions don’t work
ad_personalization	Personalised ads and remarketing	The visitor isn’t added to remarketing lists

Consent Mode can be set up in two ways. In basic, Google’s tags don’t load at all before “Accept”. In advanced, they load from the start with everything “denied” and, if the visitor says no, send only cookieless pings. In both, Google Ads estimates the conversions it didn’t see with a model: in advanced, a model for your own account; in basic, a general one. Basic is the more conservative. Which one suits you is for you to decide with whoever advises you on personal data.

A common mistake: a banner that blocks the tags, without Consent Mode. Then Google can’t confirm the visitor’s choice, and you lose data. The model’s results appear in reports after at least 7 full days with Consent Mode.

Cookies don’t always last until the purchase: the customer sees the ad on their phone and buys on their computer, or the cookies have been cleared in between. Enhanced conversions send the buyer’s email or phone number with the purchase, hashed with SHA-256, a one-way conversion that can’t be read back as text. That lets Google match the purchase more accurately to the click that brought it.

The condition is the buyer’s consent: without ad_user_data, enhanced conversions don’t work. Google is now combining enhanced conversions for purchases on the site and for leads into a single setting.

On many Greek eshops, part of the sales close outside the site: the customer sees the ad and phones, or asks for a wholesale quote. These sales reach Google Ads only if you send them, through offline conversion import. It takes three things:

1. The click ID. When a visitor comes from an ad, the page address carries an ID for the click, the gclid. The site keeps it and passes it, with the form or the order, to your business software or CRM.
2. The sale with its value. When the sale closes, it’s sent to Google Ads with the click ID, the date and the value.
3. The right route. From 15 June 2026, Google takes these uploads through the Data Manager API, and the old route through the Google Ads API is closing.

Google now recommends enhanced conversions for leads, a newer form of the same import that also matches the sale by the customer’s email or phone number. Even then, it advises sending the gclid where there is one. Here too, you send only what the customer’s consent allows.

If you work with Odoo, the campaign and source of every inquiry (the UTMs) are already recorded on opportunities and orders. See how we send sales from Odoo to Google Ads.

1. Only the purchase as a primary conversion. Everything else secondary.
2. The order number on every purchase, so it never counts twice.
3. The purchase from one source in the “Conversions” column: either the Google Ads tag or GA4.
4. The value written down and the same everywhere: with or without VAT and shipping.
5. The banks’ domains in GA4’s unwanted referrals.
6. A banner that follows recommendations 1/2020, with “Reject” beside “Accept”, and Consent Mode v2.
7. Enhanced conversions switched on, for those who give consent.
8. Phone and wholesale sales with their gclid, from your business software into Google Ads.

Finally, place one test order with “Accept” and one with “Reject”, and check in Google Ads and in GA4 what arrived each time. If something doesn’t add up, ask us for a tracking check.