Why did my Google Ads conversions drop after adding a cookie banner?

A drop is expected at first: when visitors decline cookies, Google can no longer observe their conversions directly. What matters is whether the banner is sending Consent Mode v2 signals. With correct signals, Google models conversions for denied visitors and recovers much of the lost reporting.

What actually changed

Before the banner, every visitor was measurable. After the banner, visitors who decline become invisible to your ad tags, so recorded conversions fall even if real sales are unchanged. A noticeable share of visitors decline, especially on mobile and in privacy-conscious markets.

Check the consent signals first

The most common cause of a worse-than-expected drop is a banner that blocks tags but never fires the consent state. Without ad_storage, ad_user_data, and ad_personalization signals, Google cannot model anything. Verify the signals in Google Tag Manager's consent overview before changing anything else.

Recovering the data

With Consent Mode v2 in advanced mode, denied visitors still send cookieless pings that feed Google's conversion modeling. Over a few weeks this typically restores a meaningful portion of reported conversions. The banner should also load fast and avoid dark patterns, since a confusing banner inflates declines.