Quick answer: Ad platform numbers don’t match because each takes credit for its own touch, uses different windows and models some conversions.
It’s one of the most common questions business owners ask: “Facebook says I got 30 leads, Google Ads says 25, Analytics says 18, and I only received 22. Which is right?” The honest answer is that none of the platform numbers is “the truth”. Your inbox or CRM is. But the gaps have clear causes.
Reason 1: Each platform takes credit for its own touch
Someone sees your Facebook ad on Monday, searches your business on Google on Wednesday, clicks a Google ad and enquires. Meta counts it (they clicked or viewed within its window). Google Ads counts it (they clicked a Google ad). One lead, two platforms claiming it.
GA4 usually credits the last non-direct click to one source, so it only counts the lead once, for Google.
Reason 2: Different attribution windows
- Meta’s default: 7-day click, 1-day engage-through and 1-day view
- Google Ads: usually 30-day click (adjustable), with data-driven attribution
- GA4: data-driven attribution across channels, with its own lookback windows
A lead 10 days after a Facebook click counts in Google Ads (if they also clicked there) but not in Meta’s default report. See how to read your Facebook ads results.
Reason 3: Conversion date vs click date
Google Ads reports conversions against the date of the click. GA4 reports against the date of the conversion. Meta reports by the date of the ad interaction by default. So “last week” means slightly different things in each.
Reason 4: Modelling and privacy gaps
When browsers block cookies or people decline consent, platforms model some conversions they can’t observe directly. Google Ads and Meta both include modelled conversions. GA4 can too, depending on consent settings. Real people, estimated counts.
Reason 5: Tracking errors
Often the biggest gap isn’t attribution at all. It’s:
- A conversion firing on page load as well as on submit
- The pixel counting a thank-you page someone refreshed
- Spam form submissions counted as leads
- One platform tracking calls and another not
- Forms that send email but don’t fire any event
See signs your ad tracking is broken.
Which number to trust
- Your CRM or inbox for the true number of leads and where they came from (ask “how did you find us?” and capture UTMs and click IDs in hidden form fields).
- Each ad platform for optimising *within* that platform. Their numbers are what their algorithms learn from.
- GA4 for comparing channels side by side with one consistent method.
How to get the numbers closer
- Make sure each lead fires one conversion event, only on successful submission
- Use deduplication for Meta’s pixel and Conversions API
- Record the source (UTMs, gclid, fbclid) with every lead in your CRM
- Use the same date range and compare by conversion date where possible
- Use 7-day click in Meta when comparing against other sources
- Accept a gap of roughly 10 to 30% as normal
The real goal
Rather than forcing the platforms to agree, measure what matters: total leads and total ad spend across all channels, and cost per customer from your CRM. If total spend goes up and total real leads go up proportionately, your ads are working, whichever platform claims the credit. See cost per lead explained.
Sources and further reading
Written by Gregory
20 years building websites and running lead generation, mostly with my own money on the line. Based in Sydney, working with clients worldwide. How I work →