Basic or Advanced Consent Mode: What Each One Costs You

Most Consent Mode conversations stop at whether you have it. That is the wrong question by about six months. If you advertise with Google in the EEA or UK you almost certainly have some version of it by now, because the alternative was watching audience features switch themselves off.

The question that actually decides how much data you keep is which version you are running. Basic and advanced are both Consent Mode. They behave completely differently before a visitor has chosen anything, and the gap between them shows up as a gap in your reported conversions.

Nobody chooses between them deliberately. It is usually decided by whichever setting the CMP wizard defaulted to, and then never looked at again.

What is the difference between basic and advanced consent mode?

It comes down to one thing: whether Google's tags load before the visitor answers the banner.

Basic mode holds the tags back. Nothing Google-related loads until consent is granted. A visitor who declines, or who leaves without touching the banner, produces no Google request at all. From Google's side that person did not exist.

Advanced mode loads the tags immediately, in a restricted state. They cannot read or write cookies and they carry no identifiers, but they do send a request, and that request carries the consent state along with it. If the visitor then accepts, the state is updated and normal measurement begins. If they decline, the tags keep running in that restricted state for the rest of the visit.

The names undersell the difference. This is not a small configuration detail with a better and a worse option. It is a decision about whether a request leaves the browser of someone who said no.

What does advanced mode actually send before consent?

Worth being precise here, because both the sales pitch and the objection tend to overstate it.

A cookieless ping contains no analytics cookie, no advertising cookie, and no identifier that ties the visit to a previous one or to a person. It does carry what any HTTP request carries: a timestamp, the page, the referrer, the user agent, and an IP address that Google's documentation says is used for coarse geography and not stored.

So: not tracking in the sense most people mean, and not nothing either. The visitor's browser contacted Google after they declined. Whether that is acceptable is a question for whoever advises you on privacy law, and the honest answer is that it has been argued about since the feature launched. We configure and verify consent tooling. We do not give legal advice, and anyone who tells you this question has one obvious answer is selling something.

What do you get for it?

Conversion modelling, which is the entire commercial argument for advanced mode.

Those pings tell Google that something happened, without saying who it happened to. Given enough of them, Google can estimate the conversions it could not observe directly and report them alongside the ones it did. In basic mode there is nothing to model from, because declining visitors produced no signal at all. Your reported conversions are only the consenting ones.

That matters more than the reporting gap suggests, because the numbers do not just sit in a dashboard. Smart bidding learns from them. If a third of your conversions are invisible, and the invisible third is not randomly distributed across campaigns, bidding optimises toward the campaigns whose users happen to accept cookies more often. The bias is quiet and it compounds.

Modelling is not free, though. It needs volume, and Google publishes thresholds that have moved more than once. Below them you get the privacy trade-off of advanced mode with none of the recovered conversions. Check the current requirements against your own traffic before assuming advanced mode will pay for itself, because on a small site it may simply not.

Why would anyone choose basic mode then?

Three reasons, and the first is the serious one.

A defensible position on what a declined visitor produces. If your organisation's answer is that no means no request, basic mode is that answer implemented. Nonprofits handling donor data and anyone in health or finance often land here, and they are not being naive.

Simplicity. Basic mode is easier to reason about and easier to demonstrate. You can show someone a network tab with nothing in it, which is a much shorter conversation than explaining what a cookieless ping is.

It may make no difference. Below the modelling thresholds, advanced mode buys you nothing measurable. If you are a small site with a few hundred conversions a month, the honest comparison is not advanced versus basic, it is a privacy trade-off versus nothing in return.

The case for advanced is straightforward where it applies: meaningful paid spend, meaningful EEA or UK traffic, and enough volume to model from. That is a real set of conditions, not a default.

Which one am I running right now?

Open your own site in a private window, decline the banner, and watch the network tab for requests to Google.

No Google requests after a decline means basic mode, or no Consent Mode at all, and those two look identical from outside. Check your tag setup to tell them apart.

Google requests carrying gcs=G100 means advanced mode, working correctly. The tags are running in their restricted state and the denial is being reported.

Google requests carrying gcs=G111 after a decline means something is broken. The banner is not sending its update, or is sending the wrong one, and you are tracking people who declined. That is the one result on this list that needs fixing today rather than discussing. There is a fuller walkthrough of that test in our piece on whether rejecting cookies actually stops tracking.

Do this from an EEA or UK IP if that is the traffic you care about, since region-specific banner behaviour is common and what you see from elsewhere may not be what those visitors get.

How do I switch to advanced mode?

The mechanism is simple. The ordering is where implementations fail.

Consent Mode needs a default state set before any Google tag fires, declaring everything denied. Then, when the visitor chooses, an update revises it. Get those two in the wrong order, or let a tag fire in the gap between them, and that tag runs with no consent state at all.

In Google Tag Manager, the default belongs on the Consent Initialization trigger, which is built to run before everything else. Most certified CMPs will place it for you. The failure mode to look for is a tag somebody added with a page view trigger that now fires ahead of the consent default, which the container's consent overview will show you.

Then test both paths. Accept and confirm you see normal measurement with cookies set. Decline and confirm tags still fire with gcs=G100, and that no _ga or _gcl cookies appear. A decline path that produces no requests at all means you are still on basic, whatever the CMP settings screen claims.

What advanced mode does not do

It does not make you compliant. Consent Mode is how Google's tags respond to a consent signal. Collecting that signal lawfully, with a banner that offers a real choice and honours it, is the CMP's job and your policy's job.

It does not recover the individual. Modelled conversions are an estimate at the aggregate level. You cannot look up a modelled conversion and find a person, and you should not build audiences or outreach as though you could.

It does not apply only to Google. Your Meta, LinkedIn and TikTok tags do not read Google's consent signals. They need their own consent conditions, and the most common finding in a consent audit is a Google side that is configured immaculately sitting next to a pixel that fires no matter what anyone clicks.

Pick the mode deliberately, implement the ordering correctly, then test the decline path rather than trusting the settings screen. Most of the failures we find are not the choice between basic and advanced. They are implementations that believe they are advanced and are not.

FAQ

What is the difference between basic and advanced consent mode?

Basic mode prevents Google tags from loading until consent is granted, so a visitor who declines produces no Google request at all. Advanced mode loads the tags immediately in a restricted state where they cannot read or write cookies, and they send cookieless pings that carry the consent state. Advanced mode enables conversion modelling; basic mode does not, because there is no signal to model from.

Does advanced consent mode send data before consent?

It sends a request containing no cookies and no identifier tying the visit to a person or to a previous session. That request does carry the things any HTTP request carries, including the page, referrer, user agent and an IP address. It is not tracking in the usual sense, and it is also not nothing, which is why the choice deserves a deliberate decision rather than a default.

Do I need advanced consent mode for conversion modelling?

Yes. Modelling estimates conversions from the cookieless pings that advanced mode sends for non-consenting users. Basic mode produces no such signal, so there is nothing to model from and your reported conversions include only consenting users. Modelling also requires meeting Google's volume thresholds, which have changed more than once and are worth checking against your own traffic.

How do I tell if I have basic or advanced consent mode?

Decline your own cookie banner in a private window and watch the network tab. No Google requests means basic mode or no Consent Mode at all. Requests carrying a gcs value of G100 mean advanced mode is working. Requests carrying G111 after a decline mean the banner's update is not reaching Google and people who declined are being tracked.

Is advanced consent mode GDPR compliant?

That is a legal question rather than a technical one, and it has been argued over since the feature launched. Consent Mode governs how Google's tags respond to a consent signal; it does not collect that signal or make your banner lawful. Take the question to whoever advises you on privacy law, and decide the mode with that advice rather than from the default in a CMP wizard.