A cookie banner isn't just a legal requirement: if it's set up badly, Google Ads and Analytics work from incomplete data. Here's a plain-language summary of when you need consent, what Consent Mode v2 is, and what to check.
This article is general information, not legal advice; review your own situation with a data protection expert.
When do you need cookie consent?
- Not needed for cookies strictly necessary for the site to work: sign-in, basket, security, the cookie setting itself.
- Needed for everything else: analytics (e.g. Google Analytics), advertising and remarketing tags (Google Ads, Meta, LinkedIn), embedded content that sets cookies.
- Valid consent: explicit (not pre-ticked), rejecting is as easy as accepting, and it can be withdrawn later.
What is Consent Mode v2?
A signalling system between your website and Google's tools. Based on the visitor's choice, the cookie banner sets four switches: analytics storage, ad storage, sending user data for ads, and personalised ads. Google adjusts what it measures and stores accordingly.
- Basic mode: without consent, Google tags don't load at all. Simplest, but you have no data on visitors who decline.
- Advanced mode: tags load, but without consent they only send anonymous, cookieless signals, from which Google models the missing conversions.
What happens if it isn't set up?
- Google Ads conversions show up incomplete, so automated bidding learns from bad data.
- No remarketing lists are built from EU visitors.
- If tags set cookies without consent, that's a data protection risk as well.
Checklist for decision-makers
- On first load, no analytics or advertising cookies are set until the visitor has decided.
- “Reject” is as visible on the banner as “Accept”.
- The choice can be changed later, e.g. from the footer.
- The four Consent Mode v2 signals are wired up if you use Google Analytics or Google Ads.
- The privacy notice lists the cookies and providers used.
Off-the-shelf tool or custom?
Off-the-shelf services (e.g. Cookiebot, CookieYes) are quick to set up and find cookies themselves, but they charge monthly and can slow the site down. A custom solution built into the site is lighter and cheaper to maintain if you use few external services. We use a custom solution on our own site too.
Updated: 12 November 2026
