What is a conversion in digital marketing?
What counts as a conversion?
You choose the actions that matter to the business. For a shop, the main one is a purchase. Others might be a sign-up or a call. Each is set up as a conversion action in the platform.
Then the platform counts how often that action followed an ad click or interaction. That count, with its value, is what reports and automated bidding work from.
Why do tools count conversions differently?
Each tool has its own rules. Which action counts, how long after the ad, and which ad gets the credit all vary. A view-through conversion, where the person saw the ad but did not click, is one example of a rule that changes the total.
Google also separates two words. In Google Analytics 4, the term is key event. Google says conversions are specific to ads and are the ones eligible for bidding and reporting in Google Ads1. In new writing, we use key event for GA4 only.
Counts can also double when the same order arrives twice. Event deduplication is Meta's way of counting an event once when it arrives by more than one route.
For ZFD: The count that matters is the order in your shop. Every platform number is read against it. See why the numbers differ in Meta ROAS vs Shopify revenue, and which checks change a budget in an ecommerce tracking audit.
Worked example
Easily confused with
Conversion vs Key event
The GA4 name for an important event.
Conversion vs Conversion rate
Conversions divided by something. Say what: sessions, or ad interactions.
Conversion vs Conversion lift study
A test where one group sees the ads and another does not. It measures extra conversions, not counted ones.
Conversion vs Order
A real purchase in your shop. Not every counted conversion is one.
FAQ
Is a conversion always a sale?
No. It is whatever action you set up to count. It can be a sign-up, a call or a purchase.
Is a conversion the same as a key event?
Not in Google's wording. Key event is the GA4 term. Conversion is used for Google Ads1.
Does a conversion prove the ad caused the action?
No. It shows an action followed an ad. A test tells you how many would have happened anyway.
Sources
Let’s find what’s actually working.
Next step. See how counted conversions turn into return on explicit assumptions. Use the Is your ROAS real? calculator.