GA4 and Google Ads almost never show the same conversion numbers, and clients often think their tracking is broken. Some difference is normal. The key is knowing which differences are expected and which point to a real problem.
Different attribution models
Google Ads credits conversions to the date of the ad click. GA4 credits them to the date the conversion happened. A lead that clicked on Monday and converted on Friday appears on different days in each tool.
Different counting methods
A Google Ads conversion action can count one conversion per click, while the GA4 key event counts every event. If a user submits your form twice, GA4 records two and Google Ads may record one.
Cross-device and modelled conversions
Google Ads includes modelled and cross-device conversions that GA4 does not always show. This usually makes Google Ads report slightly higher numbers.
When the gap is a real problem
If the difference is more than 20 to 30 percent, or one tool shows zero, something is wrong. Common causes are importing GA4 key events and also running a native Google Ads tag for the same action, or a broken link between GA4 and Google Ads.
Pick one source of truth for bidding, usually the native Google Ads tag with enhanced conversions, and use GA4 for analysis.

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