What is the __utmb cookie?
Used to distinguish new sessions and visits. This cookie is set when the GA.js javascript library is loaded and there is no existing __utmb cookie. The cookie is updated every time data is sent to the Google Analytics server.
Our October 2026 scan found it on 18 sites (1% of the 2,450 we scanned), set before any consent.
- Purpose
- Analytics
- Belongs to
- Google Analytics
- Set as
- First-party (under the site's own domain)
- Typical lifetime
- Under a day (vendor says: 30 minutes after last activity)
Sites that set __utmb before consent
The highest-ranked 18 of 18 sites.
- cornell.edu3 tracking companies
- pixiv.net3 tracking companies
- jalan.net27 tracking companies
- mbga.jp2 tracking companies
- nosv.org2 tracking companies
- fc2.com2 tracking companies
- russianfood.com6 tracking companies
- duke.edu3 tracking companies
- hatena.ne.jp19 tracking companies
- douban.com1 tracking company
Show 8 more sites
- imageshack.us2 tracking companies
- man7.org1 tracking company
- wikidot.com8 tracking companies
- dnszi.com1 tracking company
- fang.com2 tracking companies
- quicksetcloud.com3 tracking companies
- boutell.com3 tracking companies
- pp.ua1 tracking company
Related cookies
Other cookies from Google Analytics.
- _ga700 sites
- _ga_*685 sites
- _gid185 sites
- _gat*108 sites
- _gat_gtag_*55 sites
How to stop it
Declining non-essential cookies in a site's consent banner should stop __utmb being set on later visits. Blocking third-party cookies in your browser settings stops the third-party kind everywhere, and clearing cookies for a site removes any it already set.
Description from the Open Cookie Database (Apache 2.0).
Understanding this page
- How cookie lifetimes work, and why a 13-month _ga matters
What a cookie's "expires" field actually controls, why Google Analytics ships a 2-year default that many sites cut down to 13 months, and how Safari's 7-day cap on script-set cookies changes the picture.
- First-party vs third-party cookies (and why "first-party" still tracks you)
What the distinction actually means technically, why browsers only block one of the two, and how CNAME cloaking, server-side tagging and cookies like _ga let sites keep tracking under their own domain.
- How to block or limit trackers
Browser privacy settings, content blockers, Global Privacy Control and clearing cookies compared honestly — what each one actually stops, what it doesn't, and what it costs you in return.