The essentials
- Definition: a Google Ads conversion is a valuable action (a purchase, a form, a call, a sign-up) taken by someone after interacting with an ad.
- Three sources: the Google Ads tag on your site, importing GA4 key events, or importing offline data from a CRM.
- Primary or secondary: only primary conversions feed automated bidding.
- Window: 30 days after the click by default, adjustable from 1 to 90 days; view-through conversions are counted separately.
In Google Ads, a conversion is an action you define as valuable and that the tool links back to an ad interaction: a purchase, a form submission, a call, a booking, a sign-up. Without conversion tracking, Google Ads measures nothing but clicks; with it, it calculates a cost per conversion, a return on ad spend and — above all — it can optimise your bids to get more of those actions. It is the building block without which no SEA campaign can be run.
The types of conversion
| Type | Examples | How Google Ads measures it |
|---|---|---|
| On the website | Purchase, form, sign-up, a click on a button | The Google Ads tag (through Tag Manager) or a GA4 import |
| Calls | A call from the ad, from the site, from a forwarding number | Call extensions, Google forwarding numbers |
| Offline | A signed quote, an in-store sale, an appointment kept | Import from your CRM using the click identifier (gclid) |
| App | Installation, an action in the app | Firebase or a partner SDK |
| Store visits | A visit after an ad (estimated) | Google modelling, large accounts only |
Three ways to set up tracking
- The Google Ads tag : a code snippet (or a Tag Manager tag) fired on the action, with a conversion identifier and a value. This method is independent of GA4 and essential for enhanced conversions, which send hashed customer data.
- Importing from GA4 : your GA4 key events become Google Ads conversions in a few clicks, once the accounts are linked. It is the simplest method for a small business, described in connecting GA4 to Google Ads.
- Offline import : your CRM sends back to Google Ads the leads that became customers, identified by the gclid recorded at the time of the click. This is what lets you optimise on real sales rather than on form submissions.
Primary and secondary conversions
Every conversion action is marked "primary" or "secondary". Primary ones are counted in the "Conversions" column and used by automated bidding strategies; secondary ones are merely observed. A practical rule: one or two high-value primary conversions (a purchase, a quote), with the intermediate steps (add to basket, phone click) as secondary. Optimising on add-to-basket steers the algorithm towards visitors who fill baskets, not towards buyers. Choosing the bidding strategies that use these conversions is covered in detail in which bidding strategy to choose.
The settings that change your figures
| Setting | Options | Recommendation |
|---|---|---|
| Click-through conversion window | 1 to 90 days (30 by default) | Match it to your buying cycle: 7 days for impulse e-commerce, 60 to 90 in B2B |
| View-through window | 1 to 30 days | Short (1 day); these conversions are counted separately |
| Counting | One per click, or every one | "One" for leads, "every" for purchases |
| Value | Fixed, dynamic or none | Always a value, even an estimated one for a lead |
| Attribution model | Data-driven or last click | Data-driven as soon as your volume allows |
Checking and interpreting
- The status of each conversion action (Goals > Conversions) should read "Recording conversions"; "No recent conversions" signals a tag problem.
- Test the action yourself and check with the Tag Assistant extension that only one tag fires.
- Google Ads figures differ from GA4's (attribution to the date of the click, view-through conversions, windows): a gap of 10 to 30% is normal. See tracking your Google Ads performance with GA4.
- Without Consent Mode v2, conversions from European users who refuse cookies are neither measured nor modelled.
The related metrics (cost per conversion, conversion rate, ROAS) are defined in the Google Ads glossary and in the CPA.
How GreenRed helps
Rather than juggling several tools, GreenRed's Google Ads module brings these metrics together in a single dashboard, compares them over time and tells you which actions come first. You can try it free, with no card, from the Pricing.
Frequently asked questions
What is the difference between a Google Ads conversion and a GA4 key event?
The GA4 key event is for analysis in Google Analytics; the Google Ads conversion is for running and optimising campaigns. A GA4 key event can be imported as a Google Ads conversion. The figures then differ slightly, because the two tools don't attribute in the same way.
Should I use the Google Ads tag or the GA4 import?
The GA4 import is simplest and enough for most small businesses. The Google Ads tag remains necessary for enhanced conversions, for tracking independent of GA4, or when your GA4 property isn't reliable. Avoid counting the same action twice as primary.
Why does Google Ads show fractional conversions?
Because the data-driven attribution model shares one conversion between several clicks that contributed to the journey: a campaign can receive 0.4 of a conversion. The total across all campaigns remains a whole number. This is normal, and fairer than last click.
What are enhanced conversions?
A feature that sends Google, in hashed form, data the customer provided at the point of conversion (email, phone) so it can find the original click even without a cookie. They improve measurement where cookies are limited, provided you inform users and respect consent.