UTM parameters are short labels added to the end of a web address, such as utm_source, utm_medium and utm_campaign, that tell analytics tools exactly where a visit came from. They were created for Urchin, which Google later acquired and developed into its analytics products.
You add them to links in emails, SMS, social posts, QR codes and some ads. When someone clicks, Google Analytics 4 and similar tools read the tags and attribute the visit and any resulting sale to that source, medium and campaign, rather than lumping it under direct or generic referral traffic.
Retailers use them to compare newsletter against social against SMS, and to see which promotion drove sales. Venues put them on QR codes for table cards or posters to learn which placements get scanned. Google Ads uses its own auto-tagging, so UTMs are mainly for non-Google sources.
Keep naming consistent. Mixed capitalisation, for example Email versus email, splits results into separate rows. Keep a shared naming guide or spreadsheet, avoid using UTMs on links within your own site, because they can overwrite the original source, and never put personal information in them.
Consistent tags turn marketing from a guess into a comparison. RetailCare configures analytics and campaign tracking for retail and hospitality clients.