How do I find out which marketing channel actually drives revenue?
Short answer
Neither tool can answer this alone: a payment processor records every sale but never sees where the visitor came from, and analytics records the channel but usually undercounts or misses purchases entirely. The practical join is to compare sessions by channel from analytics against orders and revenue from your payment processor for the same period, then judge each channel against the site-wide conversion rate. That ranks channels by the money they produce rather than by the traffic they send, which is the comparison that changes budget decisions.
Why each tool answers only half
- Your payment processor sees the charge, the amount and the customer. It has no idea whether that person arrived from search, an ad, an email or a link a friend sent them.
- Your analytics sees the channel, but only records a purchase if a tag fired in the browser — which ad blockers, tracking prevention, declined cookie banners and abandoned confirmation pages routinely prevent.
So the tool that knows the money is blind to the source, and the tool that knows the source is unreliable about the money.
The comparison that works
- Pull sessions by default channel group from analytics for a period long enough to matter — a month, not a week.
- Pull successful charges and total revenue from your payment processor for the same period and timezone.
- Compute the site-wide conversion rate as orders divided by total sessions.
- Rank channels by sessions, and judge each against that site-wide rate.
This does not give you per-channel revenue precisely, and any tool claiming it does from these two sources alone is modelling rather than measuring. What it gives you is a reliable ranking and a reliable total, which is enough to decide where the next pound goes.
Revenue per session beats conversion rate for comparing channels
A channel can convert well and still be worth less than one that converts poorly, if the orders it produces are small.
Revenue divided by sessions folds both effects into one number. It is the closest single figure to "what is a visit from this channel worth", and it is the one to rank on.
What this cannot tell you
It cannot attribute a specific sale to a specific channel, because the two systems share no identifier.
It also credits the last known channel rather than the whole journey. Someone who found you through search, left, and returned directly is counted as direct. Treat the ranking as a strong signal, not a proof.