Google Analytics Cookies (v2) Cheat Sheet by Jay Taylor
An overview of the anatomy of the cookies set and used by Google Analytics.
__utma (Visitor cookie)
Each group is separated by a period character. All times stored are UNIX timestamps. For new visits the three times in this cookie will all be the same.
__utmb (Session cookie)
Each group is separated by a period character. All times stored are UNIX timestamps.
__utmc (Session cookie)
This cookie is deprecated due to session handling changes within Analytics, but is still set by ga.js. Sessions now only end when the __utmb cookie expires.
__utmv (Custom Variable cookie)
Each group is separated by a period character. This cookie can only be created by using Google Analytics' deprecated _setVar() method. Calling this method sets this cookie and automatically sends the data to Google Analytics via a __utm.gif request.
__utmmobile (Mobile Visitor cookie)
This cookie is only created by the Google Analytics mobile tracking SDK. It stores an ID generated by MD5 hashing several possible values, and then returning a substring of the result prefixed with '0x' - this serves as a unique visitor ID.
__utmz (Campaign cookie)
Each group is separated by a period character. The campaign parameters are a single URL-encoded string, separated by pipe '|' characters. They can include:
* the __utmb cookie will only expire after thirty minutes of no interaction with Google Analytics, i.e.: idle time.