Definition
Affiliate conversion rate
A program's conversion rate is the share of affiliate clicks that end in a sale. It means nothing until you say what counts as a conversion.
One to five percent is the usual SaaS range when counting paying customers. The figure climbs a lot if you count free-trial sign-ups — hence the first rule: say what you measure. Two programs both quoting “8%” while counting different things are not comparable, and an affiliate who finds out afterwards stops trusting the rest.
Three factors move it, in this order: how well the affiliate's audience fits the product, the landing page — a deep link to the page that keeps the promise converts better than a drop on the homepage — and sign-up friction.
The most useful reading is not the absolute value but the gap with the site's overall conversion rate. Affiliate traffic converting much worse than direct traffic points to a targeting problem, or incentivised traffic; affiliate traffic converting better says you have a channel, and that is the moment to put resources behind it.
Related terms
EPC (earnings per click)
EPC is the average revenue a click earns the affiliate: commissions earned divided by clicks sent. It is the first number an affiliate looks at.
Deep link
A deep link is an affiliate link pointing at an internal page — pricing, an article, a feature — rather than the homepage.
Affiliate-driven MRR
Affiliate-driven MRR is the share of monthly recurring revenue brought in by affiliates. It is the number that says whether a program is a channel or a gadget.