What is the _fbc cookie?
_fbc is a first-party HTTP cookie, but it's created by the Meta Pixel code installed on a website, not by facebook.com directly. It's generated automatically by the Meta Pixel script when a visitor arrives via a link containing the fbclid parameter, which Facebook appends to URLs shared in ads or posts.
The cookie only appears for visitors who clicked through from a Facebook or Instagram ad or link — not for every site visitor. It's set on the domain of the site being visited, not on facebook.com.
What data it stores
The cookie value typically encodes a version of the fbclid parameter from the click URL, along with a timestamp and a format-version indicator. It does not directly contain the user's name or contact details, but it lets Meta associate the visit with the ad account and, indirectly, with the Facebook profile that generated the click.
The data is sent to Meta's servers via the Meta Pixel script installed on the site (and optionally via server-side Conversions API), to link the site visit and any resulting conversion back to the ad campaign that drove it.
What it is used for
The purpose of _fbc is conversion attribution in Meta Ads: it lets advertisers see which Facebook or Instagram ads actually generated visits, form submissions, or purchases on their site. Without this cookie, Meta Pixel cannot connect an on-site action to the specific ad that brought the visitor there.
For a website owner, the cookie is useful only if they run paid campaigns on Meta and want accurate conversion reporting in Ads Manager. It serves no functional purpose for the visitor.
Does it require consent?
_fbc is classified as a marketing cookie (advertising/tracking), used for ad attribution and, indirectly, behavioral profiling within the Meta ecosystem. Under the ePrivacy Directive (as transposed in Romania via Law 506/2004) and GDPR, this type of cookie requires the visitor's prior, explicit, and informed consent — obtained through a consent banner — before Meta Pixel is loaded.
- The site owner must list _fbc and Meta Pixel in the cookie policy.
- The Meta Pixel script must be technically blocked until consent for the marketing category is given.
- Consent must be as easy to withdraw as it was to give.
How to block or delete _fbc
A visitor can delete or block _fbc through browser settings (Chrome, Firefox, Safari, Edge — cookies and site data section), or use tracking-blocking extensions. Blocking Meta Pixel in the browser (e.g. anti-tracking extensions) also prevents the cookie from being set.
For site owners, blocking needs to happen at the site level, not just through visitor instructions: the Meta Pixel script must be prevented from running until the visitor accepts the marketing category. A consent management platform like CookieFix can automatically block Meta Pixel from loading (and thus prevent _fbc from being set) until consent is obtained, removing the need to manually rewrite the tracking code on the site.
Frequently asked questions
It's a marketing cookie generated by Meta Pixel when a visitor lands on a site after clicking a Facebook or Instagram ad, used to attribute conversions in Meta Ads.
Yes, it's a marketing/tracking cookie and requires the visitor's prior consent before being set, under the ePrivacy rules (Law 506/2004 in Romania) and GDPR.
The typical duration is around 2 years from when it's set, though Meta may update this interval, so site owners should check periodically.
The simplest way is a CMP that prevents Meta Pixel from loading until the visitor accepts the marketing category, combined with listing the cookie in your cookie policy.