If you send traffic to your site from a newsletter, social posts or a partner’s page, Google Analytics 4 (GA4) can only tell those visits apart if the links carry campaign tags. This guide is for marketers, bloggers and small business owners who want a simple, consistent way to tag links with UTM parameters and then find the results in GA4.
What UTM parameters do in GA4
UTM parameters are key-value pairs added to the end of a URL, such as ?utm_source=newsletter&utm_medium=email&utm_campaign=spring_sale. When someone clicks the link, GA4 reads the values and attaches them to the session. Google’s help page on collecting campaign data with custom URLs says to add a ? before the first parameter, separate pairs with &, and notes the parameters can appear in any order.
Without tags, a click from an email app or a private message often shows up as direct traffic or a generic referral. With tags, you decide how the visit is labelled.
The parameters GA4 documents
Google’s page lists nine parameters. Google’s guidance is that when you add parameters to a URL, you should always use utm_source, utm_medium and utm_campaign. The same page warns that missing parameters result in “(not set)” values in reporting.
| Parameter | What it describes | Example values from Google |
|---|---|---|
utm_id | Campaign ID for a specific campaign or promotion | None given |
utm_source | The referrer | google, newsletter4, billboard |
utm_medium | The marketing medium | cpc, banner, email |
utm_campaign | Product, slogan or promo code | spring_sale |
utm_source_platform | Platform directing traffic to the property | Search Ads 360, Display & Video 360 |
utm_term | Paid keyword | None given |
utm_content | Tells creatives apart, such as two links in one email | None given |
utm_creative_format | Type of creative | display, native, video, search |
utm_marketing_tactic | Targeting criteria applied to a campaign | remarketing, prospecting |
Two details matter. First, Google states that utm_creative_format and utm_marketing_tactic are not currently reported in Google Analytics properties, so tagging them gains you little today. Second, the traffic-source dimensions page maps the other UTMs to GA4 dimensions: utm_source becomes “Session manual source”, utm_medium becomes “Session manual medium”, utm_content becomes “Session manual ad content”, and so on. That page does not map utm_id to any dimension; it only recommends setting it.
For most small sites, the practical set is utm_source, utm_medium and utm_campaign, plus utm_content when you need to compare two links in the same message.
A simple naming convention
Google’s page says parameter values are case sensitive: utm_source=google is different from utm_source=Google. It recommends lowercase throughout, one unique source per platform, one medium per channel, and a campaign value that matches the exact campaign name. Building on that, here is a convention that is easy to follow:
- All lowercase, no spaces. Use underscores or hyphens between words, and pick one and stick to it.
- Source = where the link lives. Examples:
newsletter,linkedin,facebook,partner_acme. - Medium = the type of channel. Examples:
email,social,referral. Keep this list short. - Campaign = the initiative. Include a date or theme, such as
2026_11_guide_launch. - Content = which link. Examples:
header_button,footer_text.
The medium values deserve care. GA4 groups sessions into default channel groups based on source and medium, so a made-up medium may land in an unexpected group. The help pages cited here do not list the exact rules, so check how your own test links are classified before rolling a convention out.
Keep a small tracking spreadsheet
A shared spreadsheet is the cheapest way to stop inconsistency. One row per tagged link, with these columns:
| Column | Purpose |
|---|---|
| Date created and owner | Who to ask about a link |
| Destination URL | The clean page address, without tags |
| Source, medium, campaign, content | The exact values used |
| Full tagged URL | Copy and paste from here |
| Where it was placed | Which email, post or partner page |
Add a second tab listing the approved sources and mediums. Anyone building a link picks from that list instead of typing a new value. If you use dropdown validation, typos such as “Newsletter” versus “newsletter” cannot happen.
Build links with Google’s Campaign URL Builder
Google offers a free Campaign URL Builder at ga-dev-tools.google. It lets you enter your page address and campaign values and returns a finished link. The parameter definitions above come from Google’s help pages. When you use the builder:
- Paste the full destination URL, including
https://. - Fill in source, medium and campaign from your approved list, in lowercase.
- Add content only if you will compare variations.
- Copy the result into your tracking spreadsheet, then into the email or post.
- Click the link yourself and confirm it lands on the right page with the tags intact.
Long links look untidy in social posts. A link shortener can help, but test that it passes the full query string to your page.
Where to see the data in GA4
Sign in to Google Analytics, choose Reports, then Acquisition > Traffic acquisition. Google describes this report as showing where new and returning users come from, and its default dimension is Session default channel grouping. To see your tags, change the primary dimension to Session source / medium, which Google describes as the source and medium associated with a new session. Google points to a separate help article, “Change dimensions in detail reports”, for the steps. To see campaign names, look for the campaign dimension in the same way.
The User acquisition report is different: it covers where new users came from, based on first-user dimensions. For judging a specific newsletter send, session-based Traffic acquisition is usually the better fit.
Tagged traffic is most useful when you also know what visitors did next. See our guide on setting up GA4 key events for a small business site, and if you want a recurring view, building a monthly marketing report in Looker Studio.
Common mistakes
Inconsistent capitalisation and spelling
Because values are case sensitive, “Email”, “email” and “e-mail” create three separate rows in your reports. Lowercase everything and use the approved list.
Tagging internal links
Do not add UTMs to links between pages on your own site, such as a banner linking to another post. The GA4 help pages cited here do not address internal links, so this is a cautious practice rather than a documented rule: a tag on an internal click can overwrite the original source information with your own site’s label, hiding where the visitor really came from. Use event tracking to measure internal banners instead.
Tagging Google Ads links when auto-tagging is on
Auto-tagging adds a GCLID parameter to your ad’s landing URL. Google Ads Help states that in GA4, auto-tagging is prioritised over manual tagging because there is no override option. The traffic-source dimensions page adds that when both are present, auto-tagged values are used for source and medium, while utm_content and utm_term still feed the Manual ad content and Manual term dimensions. Manual UTMs on ad links are therefore redundant for source and medium; leave auto-tagging on unless you have a deliberate reason to use manual tagging. Our post on Google Ads conversion tracking with the tag or GA4 import covers related setup choices.
Leaving out required values
A link with only utm_campaign will produce “(not set)” in other fields. Always include source, medium and campaign.
Putting private data in a tag
URLs are visible to the recipient and get stored in reports. Never put names, email addresses or other personal details in UTM values.
Key takeaways
- Always use
utm_source,utm_mediumandutm_campaign; addutm_contentto compare links. - Values are case sensitive, so use lowercase and a fixed list of sources and mediums.
- Log every tagged link in a shared spreadsheet and test it before publishing.
- Check results under Reports > Acquisition > Traffic acquisition, using Session source / medium.
- Skip UTMs on internal links, and do not add manual tags to Google Ads links when auto-tagging is on.
FAQ
Which UTM parameters does GA4 support?
Google documents nine: utm_id, utm_source, utm_medium, utm_campaign, utm_source_platform, utm_term, utm_content, utm_creative_format and utm_marketing_tactic. The last two are not currently reported.
Are UTM values case sensitive?
Yes. Google’s help page gives the example that utm_source=google differs from utm_source=Google, and recommends lowercase.
Why do I see “(not set)” in my reports?
Google says missing UTM parameters result in “(not set)” values. Check that each tagged link includes source, medium and campaign.
Should I tag Google Ads links manually?
Generally not when auto-tagging is on. Google Ads Help says GA4 prioritises auto-tagging over manual tagging, with no override option.