How do ESPs count unique vs total clicks?

ESPs track both unique clicks and total clicks, which measure different behaviors.

Total clicks: Every click event counts, regardless of who clicked. If one person clicks a link three times, that's three total clicks. This measures overall engagement volume and link attractiveness.

Unique clicks: Counts one click per recipient, no matter how many times they clicked. The same person clicking three times counts as one unique click. This measures how many people engaged.

Calculation example:

Sent to 1,000 recipients

50 people clicked links

Those 50 people clicked a total of 120 times

Unique clicks: 50

Total clicks: 120

Unique click rate: 5% (50/1000)

Which to use:

Unique clicks/rates: Better for measuring engagement reach and comparing campaigns

Total clicks: Useful for understanding content engagement depth and link popularity

High total-to-unique ratio suggests recipients found content engaging enough to click multiple times or explore multiple links. Low ratio might indicate single-purpose emails (one CTA, one action).

ESPs identify unique clicks by tracking recipient identifiers embedded in wrapped URLs. They know which specific subscriber clicked, not just that someone clicked.