EPC calculator
A program paying 50% sounds better than one paying 30%. Whether it is depends entirely on how many of your clicks turn into money, and that is what EPC measures.
Why EPC and not commission rate
EPC is total commission ÷ total clicks. It collapses commission rate, conversion rate, average order value and approval rate into one number, which is why it is the figure affiliate managers actually quote to each other.
A 50% program that converts poorly can have a lower EPC than a 20% program that converts well. The rate on the landing page tells you nothing on its own.
Compare on the same traffic
An EPC is only meaningful for the traffic that produced it. The same program will show a different EPC on search traffic than on social, because intent differs. Comparing your own EPC against a published network average is comparing two different audiences.
What this does not model
Reversals and clawbacks after the reporting period, held reserves, and clicks that were never attributed to you because of a short cookie window. All three reduce realised EPC below the figure a dashboard shows.