Conversion
conversions / conversion action / tracked conversion
A conversion is an action you told the ad platform to count as a result, like a form or a call. The number is not a headcount. Google's One conversion setting counts one per ad click, not per person, and Microsoft calls the same two settings All and Unique.
A conversion is whatever you decided counts. That sounds glib, but it is the literal situation: somebody chose which actions get recorded, and the number on your report is the consequence of those choices rather than a fact about the world.
Google draws a line most people do not. It says conversions are specific to the context of ads, and unlike key events they are eligible for bidding and reporting in Google Ads. Key event is the umbrella word, used in Analytics. So a conversion in your ads account and a key event in your analytics are not the same thing, by Google's own definition, and comparing the two columns is comparing two different measurements.
Then there is the setting that moves the number most, and it is rarely mentioned. Google lets each conversion action count either every conversion after an interaction, or only one. Its wording for the second is exact and worth reading twice: One conversion counts only one conversion per ad click. Per click, not per person. The same customer clicking twice on two days can produce two conversions on the lowest setting.
Microsoft has the identical mechanic under different words. Its All setting counts all conversions after an ad click, and Unique counts only one, with the guidance that Unique suits leads and All suits sales. One more difference matters if you run both: Microsoft's default is All, while Google's default depends on the conversion source.
Timing does the rest. A conversion window is how long after a click a conversion still counts, and Google's default click-through window is 30 days. Change that window and the change is not retroactive, so a conversion that fell outside the old window is not counted later.
In practice
Your platform reports 40 conversions and your own records show 26 inquiries. Nothing is broken. If the account counts every conversion, a caller who also filled in a form is two. If two people converted 29 days after clicking, your sales system logged them this month and the ad platform logged them against last month's click. Same events, two honest counts, different rules.
Not the same as
- A sale
- A conversion is whichever action was configured, which is usually an inquiry rather than money.
- A person
- The setting counts per ad click, so one customer can appear more than once.
Why it matters to you
Nearly every argument about whether advertising works is really an argument about this definition. Before anyone defends or attacks a number, it is worth knowing which actions are counted, whether counting is set to every or one, and how long the window is. Those three answers usually explain the gap on their own, and they are quick to check.
What to ask or check
- 01Which actions are set up as conversions, and when did that list last change?
- 02Is each one counting every conversion or one per click?
- 03What is the conversion window, and has anybody changed it recently?
What people get wrong
That a conversion is a person, or a sale. Google's One conversion setting counts one per ad click rather than per person, and the action being counted is usually an inquiry, not money changing hands.
Red flags
- A report compared against a sales system without anyone checking the counting setting or the window first.
- Conversion actions added or changed mid-period, with the totals still presented as a like for like trend.
Where you will see it
As the Conversions and All conversions columns in Google Ads, and as Conversions and All conversions in Microsoft Advertising.