A blended TCR of 18% can hide enormous channel variance. LinkedIn can run 30%, Meta 8%, organic 25%, and the average lands in the middle. Without splitting by source you’ll over-fund the cheap-trial channels and under-fund the high-converting ones.
Building the report
Create a Table report grouped by Source. Add columns for Trials Started, New Customers (or Trial Converted), Trial Conversion Rate (calculated as a percentage), Cost-per-Trial, and Cost-per-Paying-Customer.
Sort by Cost-per-Paying-Customer ascending. The top of the table is your scaling list. Sort by Conversion Rate ascending and the bottom is your audit list — channels with poor trial quality that need creative or targeting work before more spend.
Watching for drift
TCR is a leading indicator of channel health. If a channel’s TCR drops 30% week-over-week without any other change, the algorithm has shifted who it’s showing your ads to. That’s usually a signal to refresh creative, narrow targeting, or pause the campaign before the cost-per-customer catches up.
Pair TCR with the LTV-by-source report. A channel with a low TCR but high LTV (the trials that do convert are high-value customers) is often more profitable than a channel with a high TCR but low LTV (lots of conversions to small plans).
- Sort by Cost-per-Paying-Customer ascending for the scaling list
- Sort by Trial Conversion Rate ascending for the audit list
- Watch week-over-week TCR drift as a leading indicator
- Pair with LTV-by-source for the full economic picture
What to watch for.
- Treating cost-per-trial as the headline
Cost-per-trial doesn’t predict cost-per-customer when conversion rates vary 4x by source. Always pair them.
- Ignoring small-volume channels
A channel with 10 trials at 80% TCR is more interesting than a channel with 500 at 5%. Don’t hide low-volume rows.
- Not segmenting by plan
Free-to-paid conversion looks very different from $1-trial-to-paid. Filter by plan to see real channel patterns.
Recap.
- Calculate TCR as Trial Converted ÷ Trial Started, grouped by source
- Compare against your blended TCR to find over- and under-performers
- Filter by plan to see if higher-priced plans convert at different rates per source
- Add cost-per-paying-customer (not cost-per-trial) as the headline column
- Watch TCR drift — falling rates often mean ad creative is attracting wrong-fit users