The unique click rate describes the relationship between the number of recipients who have clicked on at least one link and the total number of recipients (so unique clicks divided by total recipient number).

Multiple clicks by the same recipient are only counted once.

Example: A newsletter was sent to 10 recipients. It was opened by four of them. Of these four, one clicks on a link twice and another clicks on three different links. The unique click rate therefore translates as 2/10 = 20%.