utm_medium

utm_medium is the UTM parameter that identifies the marketing channel or delivery method bringing a visitor to your site. It is one of the three required UTM parameters in Google Analytics 4, alongside utm_source and utm_campaign. The value gets stored in GA4’s “Session medium” dimension and drives the platform’s Default Channel Grouping, which is how GA4 buckets traffic into channels like Paid Search, Email, or Organic Social.

A tagged URL with utm_medium looks like this:

https://example.com/?utm_source=newsletter&utm_medium=email&utm_campaign=spring_sale

Here, email is the utm_medium value. GA4 reads it and assigns the session to the Email channel in acquisition reports.

Why utm_medium Matters

utm_medium is the single most important field for GA4’s Default Channel Grouping. Google’s channel definitions use regex rules that read utm_medium values to decide whether a session is Paid Search, Organic Social, Email, Referral, or another channel. A wrong or missing utm_medium drops the session into “(other)” or “Unassigned”, where it skews channel-level reporting.

utm_source tells GA4 the specific platform (facebook, google, mailchimp). utm_medium tells GA4 what type of marketing channel that platform represents (social, cpc, email). Together they form the source/medium pair that appears in every traffic acquisition report.

Standard utm_medium Values

GA4 recognizes specific utm_medium values when assigning Default Channel Groupings. Using non-standard values forces traffic into “(other)” and breaks channel reporting.

Paid channels:

• cpc (paid search ads, Google’s default value)
• ppc (alternative to cpc)
• paid (some platforms use this generically)
• display (display banner ads)
• paidsocial or paid_social (paid social media ads)
• cpm (cost-per-thousand-impression buys)
• retargeting

Organic and earned channels:

• organic (organic search, set automatically by Google)
• social (organic social media posts)
• referral (links from other websites)
• email (email campaigns)
• affiliate (affiliate partner traffic)
• influencer (creator and influencer content)

Other recognized values:

• video (YouTube and other video platforms)
• banner (banner placements)
• push (push notification campaigns)
• sms (text message campaigns)
• qr (offline QR code scans)

Stick to lowercase and hyphens or underscores. Paid Social becomes paid_social or paidsocial. The exact value matters: GA4’s channel regex looks for cpc, paid_search, or anything containing paid to flag Paid Search traffic.

utm_medium vs utm_source

The two parameters answer different questions. Confusing them is the most common UTM mistake.

Parameter	Question it answers	Example values
utm_source	Where exactly did the click come from?	google, facebook, newsletter
utm_medium	What type of channel is that?	cpc, social, email, referral

A Google Ads click is tagged utm_source=google&utm_medium=cpc. An organic Google search would auto-tag as utm_source=google&utm_medium=organic. The source is identical, the medium changes. The same logic applies to Facebook: paid ads use utm_medium=paidsocial or cpc, organic posts use utm_medium=social.

utm_medium Best Practices

• Use lowercase only. GA4 treats Email and email as different mediums. Casing mistakes split traffic between two rows in every report.
• Match GA4’s expected values. Use cpc, not paid-search. Use email, not email-blast. The Default Channel Grouping reads specific strings.
• Never put the platform name in utm_medium. utm_medium=facebook is wrong. facebook is a source, not a medium.
• Standardize across the team. Pick one of cpc or ppc for paid search and stay with it. Pick one of social or paidsocial for paid social posts and document it.
• Avoid blank or generic values. link and web carry no meaning and break attribution. Always pick from the standard list.
• Tag every external link in a campaign. Untagged links default to (direct)/(none) even when the click came from a paid ad.

For teams running large campaigns, enforce naming consistency with linkutm’s UTM naming convention checker.

Frequently Asked Questions

What does utm_medium mean?

utm_medium identifies the marketing channel or delivery method that brought a visitor to your site. Common values are email, cpc, social, referral, and affiliate. It works together with utm_source to tell GA4 both what platform sent the traffic and what type of channel that platform represents.

What are common utm_medium values?

The most common values are cpc (paid search), email, social, paidsocial, display, referral, affiliate, organic, video, and banner. These match GA4’s Default Channel Grouping rules, so traffic gets categorized correctly. Always use lowercase and avoid spaces.

What is the difference between utm_medium and utm_source?

utm_source names the exact platform (google, facebook, newsletter). utm_medium names the channel type (cpc, social, email). A paid Facebook ad is tagged utm_source=facebook&utm_medium=cpc. An organic Facebook post is utm_source=facebook&utm_medium=social. Source identifies the platform, medium classifies how the traffic was delivered.

Is there an official utm_medium list?

Google does not publish a fixed list, but GA4’s Default Channel Grouping recognizes specific values for channel assignment. The standard set is cpc, ppc, paid, email, social, paidsocial, organic, referral, affiliate, display, video, banner, and push. Values outside this set get bucketed as “(other)”.

Is utm_medium case sensitive?

Yes. GA4 treats utm_medium=Email and utm_medium=email as two different mediums. The Default Channel Grouping regex is also case sensitive in most rules. Always use lowercase to keep your data consistent and your channel reporting accurate.

To build campaign links with the right utm_medium values, use the free UTM builder at linkutm.