UTM Source vs Medium
Choose a stable origin and distribution method without mixing platforms, vendors, and campaign names.
By UTMCraft / Axellier · Updated · Examples use fictional campaigns.
Ask two different questions
Source answers “which origin sent this visit?” Medium answers “what kind of distribution was it?” A newsletter from your weekly editorial list can use source=weekly_digest and medium=email. A placement bought in a partner newsletter can use source=partner_digest with the same medium.
Choose the level of source detail that your team can maintain. If you use a publishing vendor as a source today and a newsletter name tomorrow, the report mixes two different concepts. Write down your convention before sharing links.
One source can have more than one medium
Your Instagram profile link and a paid Instagram advertisement can share a platform source while using different medium values. In our example they use social and paid_social. They are local naming conventions; verify how your analytics system classifies them rather than assuming a custom label creates a reporting channel.
Do not use the campaign name as the medium. Values such as autumn_launch and october_sale describe initiatives and make it difficult to compare distribution methods across campaigns.
Profile: utm_source=instagram&utm_medium=social&utm_campaign=studio_opening Paid ad: utm_source=instagram&utm_medium=paid_social&utm_campaign=studio_opening
Make a migration explicit
Suppose old links use fb, Facebook, and facebook. Choose one spelling for future links and record the date the convention changed. Editing a naming document does not rewrite existing traffic records, printed links, or already-sent emails.
Use Compare URLs to check a replacement: source should be the intended change, while the destination and campaign remain stable. If historical reporting needs consolidation, handle that in the reporting layer instead of pretending the original values never existed.
Before you publish
- Define whether source identifies a platform, publication, or partner.
- Reuse one medium spelling per distribution method.
- Keep campaign identity out of source and medium.
- Document convention changes for whoever reads historical reports.
References and further reading
Our worked examples explain a workflow; platform behavior can change. Report a correction with a synthetic example.