Google Analytics Cookies

Google Analytics uses 4 persistent and session cookies as detailed in the table below:

NAME OF COOKIE DFAULT EXPIRATION TIME DESCRIPTION
__utmc: Session cookie used to detect when the browser window has closed. End of browser session
__utma Persistent cookie used to store the visitors unique (randomly generated) ID. The cookie is updated every time data is sent to Google Analytics. 2 years from set/update
__utmb: Persistent cookie used to determine new sessions/visits. The cookie is updated every time data is sent to Google Analytics. 30 mins from set/update
__utmz: Persistent cookie used to store the traffic source or campaign that explains how the visitor reached your site. 6 months from set/update