Short answer: A conversion counts twice when the same label sits on two tags , or one trigger fires several labels in one Ads account and 2+ are primary. We saw one of the two on 182 of 886 sites with Ads conversion tags (20.5%, 5 Nov 2026). Check: submit your form once in GTM Preview and count the Ads tags that fire.

How common are duplicate conversions?

Sample Duplicate Share

1,727-site study (Tranco top 1M), 5 Nov 2026 182 of 886 20.5%

About 1 in 5: use 20.5%. The table below is an earlier sample of 203 larger B2B SaaS vendors (4 Nov, same exact-trigger method), so its 30.0% is a different set of sites, not a second rate. Older figures we retracted: corrections .

Which setups cause them, from the GTM containers of 203 B2B SaaS sites with an Ads conversion tag (4 Nov 2026):

Pattern Sites of 203

Same label on 2+ tags 20 (9.9%)

One trigger, 2+ labels, one AW- account 49 (24.1%)

One trigger, labels in other accounts only 24 (11.8%)

Either double count 61 (30.0%)

A site can show several patterns.…