The _uetvid cookie
The Microsoft Advertising UET visitor cookie, holding an ID that recognizes returning visitors for conversions and remarketing.
_uetvid at a glance
- Cookie name
_uetvid- Vendor
- Microsoft UET
- Category
- Advertising
- Party
- First-party
- Lifetime (observed)
- 390 daysObserved median across TagPipes scans. The vendor does not document a lifetime, so this is not its configured value.
- Set on
.<your-domain>- Value format
- Visitor ID followed by extra parameters (exact encoding not documented by vendor)
- Name match
- Exactly
_uetvid
What the _uetvid cookie does
_uetvid stores a unique, anonymized visitor ID assigned by the Microsoft Advertising UET tag. UET uses it to recognize returning visitors for conversion tracking and remarketing lists. Since July 2023 it also carries an insights user ID, cookie version, expiry time, consent state and creation time.
Microsoft documents the purpose and first-party storage but not the cookie lifetime. Third-party lists vary between 1 year and 13 months; TagPipes observed a median of about 13 months. Microsoft's separate 390 day figure is how long UET data is retained, not how long the cookie lasts.
What TagPipes observed
0.70%
of sites scanned set it (288 of 41,162)
390 days
median observed lifetime
TagPipes scanned 41,162 public websites between August 11, 2026 and September 13, 2026, loading up to three pages per site in a real browser as a first-time visitor. _uetvid was present on 288 of them.
It was set as a first-party cookie on 256 sites and as a third-party cookie on 32. A site can count in both. Where it was stored as a persistent cookie, the median lifetime we recorded was 390 days.
Often found alongside
Percentage of sites with _uetvid where the other cookie was also present.
Technologies detected on the same sites
- Google Analytics on 99% of them (55% of all sites scanned)
- Microsoft UET on 99% of them (0.99% of all sites scanned)
- Google Ads on 94% of them (12% of all sites scanned)
- DoubleClick on 92% of them (11% of all sites scanned)
- Google Tag Manager on 85% of them (30% of all sites scanned)
Aggregate figures across all sites scanned. Websites of TagPipes customers are excluded, no individual site is named, and cookie values are never read or stored. Snapshot dated September 13, 2026.
How to check for _uetvid on a website
- Open the site in Chrome, then open DevTools (F12, or Cmd+Option+I on a Mac).
- Go to the Application tab and expand Cookies in the left panel.
- Select each domain listed there and look for
_uetvid. The Expires column shows when it will be deleted. - If it is not there, reload the page. Many cookies are only set after a tag has loaded, and some only after a visitor has made a consent choice.
Other Microsoft UET cookies
Sources
- Microsoft Advertising Help: UET frequently asked questions
- Microsoft Advertising Help: UET and consent FAQ
Purpose and value format checked against the vendor documentation above on . The observed lifetime and the figures under What TagPipes observed are TagPipes scan data from September 13, 2026, not values documented by the vendor. Vendors change their cookies, and sites can configure their own names and lifetimes. Browse all cookies.
Know every cookie your own site sets
TagPipes Pulse identifies the cookies dropped on your site and flags unclassified or miscategorized ones. Shield builds your cookie declaration from a real scan rather than a questionnaire.
TagPipes monitors, configures and reports. It does not determine legal compliance and does not provide legal advice. Output is informational and reflects observed state at the time of observation. Rawsoft's expertise is technology, not law; please confirm any regulatory interpretation with your own counsel.