How to use UTM parameters to track email campaigns in Google Analytics

Executive overview

Email campaigns often disappear in Google Analytics — traffic lands in "referral" or "direct" instead of "email" because the tool follows a strict, rule-based system with no tolerance for inconsistency. UTM parameters fix this by appending structured tags to every URL so GA places clicks in the correct bucket.

Getting this right lets you prove what each channel contributes and defend your budget. Getting it wrong means bad data, bad decisions, and an acquisition report no one trusts.

Tag correctly or your email traffic is invisible to the people who control your budget.

Why Google Analytics misclassifies untagged email traffic

• GA uses a rule-based lookup to assign every session to a medium — email, social, organic, referral, direct, other.
• Gmail opened in a browser registers as referral (source: mail.gmail.com).
• Outlook on desktop with no tag registers as direct.
• Medium tagged Email (capital E) or email marketing doesn't match the rule — traffic falls into "other".
• The acquisition report is the default report stakeholders use; misclassified data leads directly to misallocated budgets.

The five UTM parameters

• Medium — the broad channel bucket; must be exactly email (lowercase) for email traffic.
• Source — where the link lives within that medium; use the database name (e.g. newsletter, onboarding, premium-users), not the ESP name (e.g. salesforce, customer.io).
• Campaign — optional; ties activity across multiple sources and mediums under one label for easy filtering.
• Content — optional; distinguishes multiple links to the same destination within one send (e.g. hero-image vs cta-button).
• URL — verify the link works, doesn't redirect, and doesn't 404 before adding parameters.

Common tagging mistakes to avoid

• Using the ESP name as the source (salesforce, mailchimp) instead of the audience segment or database name.
• Capitalising the medium (Email, EMAIL, email marketing) — GA rejects all variations that don't match exactly.
• Not saving a log of UTM strings — the Google URL builder keeps no history; maintain a separate record.
• Putting sensitive or offensive labels in any parameter field — customers can see UTM values in the URL.

Reading the acquisition report correctly

• The default view assigns 100% of conversion credit to the last non-direct channel — not the first touch.
• A channel that looks low-converting in this report may have started or nurtured the journey.
• Cutting spend based on last-touch data alone is like sacking every player except the one who scores.
• Use the multi-channel funnels → assisted conversions report to see what each channel contributed at earlier stages.
• Assisted conversions often reveal that email, social, or PR drove far more value than last-touch attribution shows.

Using assisted conversions to justify channel spend

• The assisted conversions report shows the revenue each channel helped generate, even without converting the final click.
• Compare last-touch revenue (acquisition report) with assisted revenue (MCF report) side by side for stakeholder presentations.
• Paid search brand terms frequently appear to dominate last-touch — but only because earlier channels built awareness.
• Presenting both figures reframes the conversation from "which channel converted" to "how channels work together".