What are tracking cookies?
A tracking cookie is one used to recognise your browser across more than one website, so a company can build a picture of what you do online — usually to target advertising.
How tracking cookies follow you
When many different sites embed the same third party — a Facebook "like" button, a Google ad, an analytics script — that third party can set and read its own cookie on each of those sites. Because it is the same cookie ID everywhere, the third party can link "this browser visited site A, then site B, then bought something on site C" into one profile.
That cross-site recognition is the whole point of a tracking cookie, and it is what separates it from an ordinary first-party cookie that only the site you are visiting can read.
Tracking cookies vs ordinary cookies
An ordinary (first-party) cookie is set by the site in your address bar and is readable only by that site — your login session, your cart. A tracking (usually third-party) cookie is set by a different domain embedded in the page, and the same company can read it across every site it appears on.
Browsers are increasingly blocking third-party cookies by default, which is pushing trackers toward first-party and server-side methods — but the consent rules apply either way.
How to stop them
On a compliant site, clicking "Reject all" prevents tracking cookies from being set. You can also block third-party cookies in your browser settings, or use a privacy-focused browser. To see which trackers a specific site loads, run it through a scan.
Cookies like this
Scan any website and we'll list every cookie it sets — categorised, with the ones that load before consent flagged.
Related guides
General information to help you understand cookies — not legal advice.