Why Your Google Ads Conversions Drop After Adding a Cookie Banner

 

You added a cookie banner to follow the law. A week later, your Google Ads conversions fell. Many owners hit this and think the setup is broken. It is not. Let us walk through what really happens and how to fix it.

First, the cause. A cookie banner lets users say yes or no to cookies. When a user says no, Google tags cannot write cookies for that person. So Google cannot track the sale the normal way. Your reports show fewer conversions, even though your real sales did not change. The drop is a tracking gap, not a sales problem.

Now, the fix. Google Consent Mode reads the choice from your banner and passes it to Google. It does not show the banner itself. It tells Google what each visitor allowed. This lets Google act on the choice instead of losing the data.

There are two ways to run it. Basic consent mode blocks Google tags until the user clicks the banner. If the user says no, no data is sent. Advanced consent mode loads the tags with consent set to denied by default. While consent is denied, the tags send small cookieless pings. Google uses these pings to model the missing sales. Google's own documents say the advanced way builds a model made for your account, so it recovers more than the basic way.

Next, the part many people miss. In November 2023, Google moved to Consent Mode v2. It added two signals, one for ad data and one for ad personalisation. Google now needs all four signals for users in Europe. Without them, ad features like remarketing can stop for those users. You can set up Consent Mode v2 to send every signal in the right order.

One more tip. Send the consent update on the same page where the user clicks accept. If you wait for a page reload, the tags can lose data. Also give it time, because Google needs about seven full days before it reports the recovered numbers.

Seers AI connects your cookie banner to Consent Mode v2 for you, so you stay legal and keep clean data at the same time.