You are not doing anything wrong
If you have ever pulled up Google Ads, Google Analytics, Facebook Ads, and your CRM side by side for the same week and gotten four different numbers for "how many conversions did we get," that is not a sign your tracking is broken. It is the expected, default state of running marketing across more than one platform - and almost nobody explains why in plain terms, which is what this page is for.
The three real reasons, explained without jargon
1. Each platform only sees its own piece
Google Ads sees what happened after someone clicked a Google ad. Facebook Ads sees what happened after someone interacted with a Facebook ad. Google Analytics sees what happened on your website, from whatever traffic source brought them there. None of these systems can see what the others saw - they can only report on their own slice, using their own guess about what led to a conversion.
2. Each platform counts on a different clock
This is called an "attribution window" - how far back a platform is willing to look and still give itself credit. One platform might count anything within 30 days of a click; another might count 1 day of a click plus 1 day of a view. Same customer, same purchase, different math depending on which platform's clock you are reading.
3. A "conversion" does not mean the same thing everywhere
To an ad platform, a conversion is often just a form submission. To your CRM, a "lead" might not count until someone manually qualifies it. To your finance team, it might not count until money actually changes hands. Three honest counts of three different moments in the same journey - not an error, a definitional mismatch.
What to actually do about it
Do not chase perfect agreement between platforms - it does not exist, on any stack, at any company, regardless of budget. Instead:
- Pick one system as the source of truth for each specific decision (usually your CRM for revenue-based decisions, the ad platform for campaign-level optimization).
- Understand and document each platform's attribution window and definition of a conversion, so differences stop being a surprise.
- If the gap is large or growing, that is worth investigating - see our marketing attribution guide for the underlying mechanics, or get a stack audit if you suspect a real tracking gap rather than normal platform disagreement.