Consent Mode v2: how many conversions are you missing out on without it?
Without Consent Mode v2, you lose as many conversions as there are visitors who declined cookies: the purchase happens, but the account does not see it. Consent Mode v2 is Google’s mechanism that allows your ad campaigns to keep receiving conversion data after a refusal, by modelling the missing data. Version 2 adds two new parameters, ad_user_data and ad_personalization, which separate consent to send data from consent to personalisation. If they are missing or always set to denied, the account optimises against an incomplete picture and gradually becomes more expensive. The check takes about 10 minutes and is done in the browser, without any change to the website.
My name is Hristiyan Panov — a performance marketing consultant with over 5 years’ experience and over €2 000 000 managed advertising budgets for over 90 companies on Google and Meta. Below is an explanation of exactly what Consent Mode v2 does, how to check it in 10 minutes, and why not having it in place ends up costing more than a fine.
What changes when a visitor declines cookies?
Without Consent Mode, the ad tags simply do not fire. No signal is sent. The conversion exists in your shop, but Google does not recognise it.
With Consent Mode v2, the tags are always triggered, but if consent is refused, they send a signal without identifiers — no cookies, no advertising ID. Google receives the information that a conversion has taken place, without knowing who the person is. From these incomplete signals, the platform statistically models the missing conversions.
The difference in practice: in the first scenario, you lose the data completely. In the second, you lose some of it and Google provides you with an approximate estimate.
What are the two new parameters in version 2?
- ad_user_data — whether user data can be sent to Google for advertising purposes.
- ad_personalisation — whether the data can be used for personalised advertising and remarketing.
These are added to the existing ones ad_storage and analytics_storage. Without these two new parameters, retargeting audiences in the European Economic Area will stop being populated — this is the most noticeable consequence for online shops.
Each parameter takes two states: granted or denied. They are set in two stages. First the default state runs, which executes before the tags load. Then the choice from the banner supplies an updated state. If the order is reversed and the tags fire before the default, the event goes out without the parameters.
The parameters are independent of one another. A visitor can allow measurement but refuse personalisation — in that case analytics_storage is granted and ad_personalization is not. That is why GA4 can report traffic while remarketing audiences stay in place. In GTM the state is visible in the consent section of the tag. If only ad_storage and analytics_storage are present there, the banner is running on the previous version.
How can you check in 10 minutes whether it’s working?
- Open the website in a new incognito window and decline cookies.
- Launch Google Tag Assistant and check whether the tags are still firing despite the error.
- In the event details, check that all four parameters are included.
- Repeat with acceptance on the cookies and compare — when accepting them, the settings must be enabled.
- In Google Ads, open the conversion diagnostics and check whether there is a warning about missing consent.
If the tags do not trigger at all in the event of a refusal, Consent Mode has not been implemented — regardless of what the platform claims about your banner.
Why does the shortfall cost more than the fine?
A fine is a risk. Data loss is a daily expense.
An account that only sees a fraction of its conversions optimises based on a distorted picture. Campaigns that are actually profitable appear to be losing money and are paused. Campaigns that are actually losing money appear acceptable and continue to spend. The more aggressive the automatic bidding, the faster this error accumulates.
That is why, when conducting an audit, I check the consent details in the account before anything else. There is no point in arguing about budgets based on data that does not reflect reality.
Is Consent Mode sufficient on its own?
No. Consent Mode deals with situations where the user has declined consent. It does not address the issues caused by ad-blockers, browser extensions and restrictions on third-party cookies.
The two measures complement each other: server-side tracking returns the signals that the browser blocks, and Consent Mode covers those for which there is no permission. Together they restore most of the missing picture.
The dividing line is simple. If the signal disappears after the visitor has accepted cookies, the cause is technical — a blocked script, a shortened cookie lifetime, an interrupted session. This is a job for server-side. If the signal disappears on refusal, the cause is permission and it is solved by Consent Mode. The two cases already differ in the test in an incognito window.
The order of implementation matters. First sort out consent, then move the signals to the server. The reverse order carries the distorted picture to another place without fixing it. And one more clarification: server-side does not override a refusal. For a visitor who has refused, the server sends the same signal without identifiers.
What do I check during implementation?
- Is the consent banner a certified Google partner and does it submit the signals automatically?.
- Are all four parameters being transmitted correctly?.
- Is the default setting ‘no’ until an explicit choice is made?.
- Is the user’s choice remembered for subsequent visits?.
- Are the modelled conversions already appearing in the account?.
- Are retargeting audiences continuing to grow?.
The order is not random — each next point depends on the previous one. A certified banner supplies the signals itself and saves hand-written code in GTM. The parameters are read in the real event stream, not in the tag setting: the setting shows intent, the stream shows what actually went out.
The default is checked on first load in an incognito window, before any choice. The memory of the choice is checked when the website is reopened: if the banner pops up again, the choice is not being saved and every visit starts from a refusal.
The last points are the result. Modelled conversions do not appear immediately after publishing, so the account is looked at again later. The audiences are compared with their state before the change, not just with the current size.
FAQ — Frequently Asked Questions about Consent Mode v2
Is Consent Mode v2 mandatory?
For advertising to users in the European Economic Area, Google requires the transmission of consent signals. Without these, personalised advertising and remarketing to these audiences are restricted.
Will I get all my lost conversions back?
No. Modelling provides an approximation, not an exact record. The aim is for the account to make decisions based on a more complete picture, rather than to reconstruct every single record.
Is it worth it if there’s not much traffic?
Modelling requires a certain volume to be reliable. Where traffic is very low, the benefit lies primarily in compliance with Google’s requirements for advertisers in the EEA. With hundreds of conversions per month, the benefit also extends to optimisation.
Who implements it — the developer or the marketer?
This is usually set up in Google Tag Manager by the person responsible for tracking. The banner must be compatible and send the signals automatically.
How can I tell that it’s working now?
Modelled conversions appear in Google Ads, and the warning about missing consent in the diagnostics disappears. Remarketing audiences stop shrinking.
Conclusion
Consent Mode v2 is not just a legal formality. It determines how many of your actual sales the advertising account actually sees — and all other decisions are based on that figure.
If you are advertising to Bulgarian or European consumers and have not checked your consent status since the banner was implemented, start by arranging an independent review.
Request a quote for a digital audit →
Related articles: Google Ads account audit · server-side tracking · Performance Max
