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The link has more than one question mark

A second question mark in a link turns the next UTM tag into part of another value, so it never reaches reports. How to join parameters with & instead.

SymptomSome UTM tags are missing in reports, or a value shows up with ?utm_ stuck to the end of it.
Likely causeTags were added with a ? to a link that already had one, instead of with an &.
FixKeep the first ? and join every later parameter with & instead.

Short answer: In a web address, the first ? starts the query string and each parameter after it is joined with &. If a link has a second ?, everything after it is read as part of the previous value, so the next UTM tag is lost. Replace the second ? with &.

What is a query string?

Query string: the part of a link after the first ? and before any #, made of name=value pairs joined by &, where UTM tags and other parameters live.

The web address standard, RFC 3986, says the query is "indicated by the first question mark" and ends at a # or at the end of the link. A second ? doesn't start anything new. It's just a character inside a value.

What happens when a link has two question marks?

The parameter straight after the second ? is swallowed by the one before it. Analytics tools see one long, odd value and no separate tag.

Take ?id=42?utm_source=newsletter. The tool reads one parameter, id, with the value 42?utm_source=newsletter. There is no utm_source at all, so the source shows as missing.

Why does this happen?

  • Adding tags to a link that already has parameters: the page address is example.com/product?id=42, and someone adds ?utm_source=... to the end.
  • Spreadsheet formulas: a formula always joins the base link and tags with ?, even when the base link already has one.
  • Ad and email tools: a tool appends its own ? parameters to a link that already carries yours.
  • Copy and paste: a full tagged link gets pasted onto the end of another one.

Example

A product link with tags added using a second ?:

https://example.com/product?id=42?utm_source=newsletter&utm_medium=email&utm_campaign=oct

The fixed link, with & before the first UTM tag:

https://example.com/product?id=42&utm_source=newsletter&utm_medium=email&utm_campaign=oct

In the broken version, utm_medium and utm_campaign still come through, but utm_source is lost inside the id value. That's why this problem can be hard to spot: reports aren't empty, just missing one field.

How to fix it

  1. Paste the link into the link checker. It flags any link with more than one ? and lists what each parameter actually contains.
  2. Keep the first ?. Change every later ? that starts a new parameter into &.
  3. If a tool adds its own parameters, check the link after the tool has changed it, not before.
  4. In spreadsheets, check whether the base link already contains ? and join with & if it does.
  5. Use the UTM builder, which reads the existing link and adds tags with the right separator.
  6. Watch for a # too. Parameters after a # have their own problem, covered in parameters after the #.
Related

Related problems

Links A link you're sharing contains an ad click IDClick IDs such as gclid and fbclid belong to one ad click, so copying them into a link you share ties every visitor to that one click.Links Campaign link uses http instead of httpsAn http link usually has to redirect to https, and each redirect is one more chance for tracking tags to be dropped.Links The campaign link has spaces in itA space isn't allowed in a web address, so links with spaces get cut short, encoded differently or split in two.Links UTM tags come after the # in the linkAnything after # stays in the browser and is never sent to the website's server, so tags placed there are easy to lose.

Check a link →

FAQ

Common questions

Can a link have two question marks?

It can, but only the first one starts the query string. Any later `?` is treated as part of a value, so it doesn't start a new parameter.

Why is only one of my UTM tags missing?

Usually because the tag right after the second `?` was absorbed into the previous value. The tags after it, joined with `&`, still come through.

Do I need to encode a ? that's meant to be inside a value?

Inside a value, such as a link passed as a parameter, `?` should be percent-encoded as `%3F`. That keeps it from being confused with the start of a query.

Does this affect App Store and Play Store links?

Yes. Store links have their own parameters, such as `id=` on Google Play, so campaign details must be joined with `&`. See [Play Store link problems](/problems/play-store-link-problems/).

What are UTM parameters?

UTM parameters are tags added to the end of a link, such as utm_source and utm_campaign, that tell analytics tools where a visit came from. They let you see which campaign, channel and ad brought each visitor.

Which UTM parameters are required?

Use utm_source, utm_medium and utm_campaign on every campaign link. utm_term and utm_content are optional and help you compare keywords or ad variants.