Microsoft UET tag explained: Bing Ads conversion tracking

A numeric card labelled Microsoft Advertising UET in your Tag Explorer results is the tag behind conversion tracking and remarketing for ads on Bing, MSN, partner search sites and the Microsoft Audience Network. UET stands for Universal Event Tracking, and the word universal is the point: it is one tag for the whole account, not one per thing you want to measure. Paste your page into Tag Explorer to see this tag on your own site.

That design makes it behave quite differently from the social pixels sitting next to it in the same scan result. Understanding the difference saves a lot of unnecessary work.

What it actually does

The tag loads a script from bat.bing.com/bat.js and pushes activity into a queue called uetq. On its own it records page visits. If you want to report something a URL cannot express, such as a video being played, you push a custom event onto that queue.

Microsoft uses that stream for two purposes: counting conversions against goals you define in the account, and building remarketing audiences. Automated bidding depends entirely on the first, which is why an account with no working UET tag cannot use most of its own bidding features.

What the tag ID means

A UET tag ID is a plain number, no prefix, commonly eight or nine digits. It identifies one tag belonging to one Microsoft Advertising customer, and it is visible in your page source. Find yours in the conversion tracking area of the account, beside the tag name, and compare it to what a scan reports. If they differ, your conversions are landing somewhere you are not reading.

One tag can also be shared at manager account level, so a group of advertiser accounts report to it and use the audiences it builds. Sharing is to the manager account rather than to individual advertiser accounts, and once the scope is widened it cannot be narrowed again, so look for an existing shared tag before creating another.

One tag, many conversion goals

This is the part worth the reading time. The tag reports what happened. Deciding which of those things counts as a conversion is a separate exercise carried out in the account, and Microsoft supports several goal types:

• Destination goals, where reaching a particular URL counts.
• Event goals, matching a custom event the page sent.
• Duration goals and pages viewed per visit goals, both derived from ordinary browsing with no extra code.
• Offline conversion goals and in-store transaction goals, fed by data you upload rather than by the website.

Two useful consequences follow. Adding a conversion rarely needs a developer, because most new goals are just a new rule against a URL you were already recording, and a destination goal created today can start matching immediately. The flip side is that a tag alone measures nothing: plenty of accounts have a healthy UET tag, a scan that passes, and no goals defined, which reports zero conversions just as convincingly as a missing tag does.

The click ID, and conversions that happen offline

With auto-tagging enabled, Microsoft appends a click identifier called msclkid to your landing page URLs, and the UET tag writes it into a first-party cookie. That cookie is how a conversion three days later still gets credited to the right click, without depending on third party cookies, which browsers keep restricting further.

It matters after the visit ends too. If your sales happen on the phone or in a back office system rather than on a checkout page, you can upload offline conversions later against that stored click ID, so the ad that produced a real customer gets the credit rather than the one that produced the most form fills.

Which is why redirects deserve care. A tidy-up rule that strips query parameters, or a canonical redirect that drops everything after the question mark, removes msclkid before the tag can store it. Attribution then fails quietly while every installation check still passes.

What this looks like in Tag Explorer

Tag Explorer draws your page as a tree: each Tag Manager container is a branch, its tags are leaves beneath it, and anything hard coded into the page HTML sits under DIRECT ON PAGE.

UET appears as an Advertising card with the tag ID as the title and the tag type as the subtitle, with a copy button for the ID. Microsoft publishes an official template in the Tag Manager gallery, so a modern installation reports its ID cleanly. An older one is often a Custom HTML tag holding the snippet, and those show the tag type as the title with no ID and no copy button.

The useful signals are the duplicate banner with its red attention badge when the same tag ID is found from two sources, the info icon that opens a definition and the Learn more link, and the Copy for AI button if you want to hand the whole tree to whoever maintains the site.

The usual limits apply: the published container file carries the tag type and tracking ID but never the human names you gave your tags, and the tool reads the published container, so an unpublished change will not appear. A scan proves the tag is installed, not that it fired. Microsoft’s own tag helper extension, Preview mode in Tag Manager and the Network tab in your browser developer tools prove firing, and the tag status in your account proves the data arrived.

What to do if it is missing, duplicated or dead

Missing. Without the tag, conversions read zero, remarketing lists never fill and automated bidding cannot function. Create the tag in the account, install it through the official Tag Manager template with a trigger on all pages, publish, then confirm the tag status moves off inactive. If your campaigns were imported from Google Ads, treat this as expected rather than a fault: the import cannot touch your website.

Duplicated. The same tag ID from two sources double counts conversions and inflates remarketing lists. Keep the Tag Manager copy, remove the hard coded one, and check whether a website platform integration was quietly adding it as well. Two different UET IDs usually means two accounts were set up over the years: identify which one is billing you, and check whether the other holds a shared audience someone still depends on.

Dead or stale. There is no retired version of UET to remove, so a tag is never dead by age. What goes stale is a tag belonging to an account nobody can access. Since UET audiences must reach a minimum size before they can be used, an abandoned tag is usually building lists that will never serve an ad while still loading a script for every visitor. Replace it with a tag in an account you control.

Related guides

• Google Ads conversion tracking explained
• LinkedIn Insight Tag explained
• The Conversion Linker explained
• GTM containers explained
• Custom HTML tags explained

Run a scan with Tag Explorer to confirm which UET tag ID your pages report to, then go and check that at least one conversion goal exists against it. Those two answers together tell you whether your Microsoft spend is being measured at all, and getting that pairing right before increasing a budget is the same discipline we apply to the ChatGPT Ads campaigns we run for clients.