I had read your post before it had been even been responded to. I was gonna respond, but one thing led to another and I also feared being flamed.

It is impossible to create a formula, especially with UKnaked without a history of data. Each site is quite unique.

As many wrote above, the trial is "converted" in the first month. A pay site should have 50-70% converted from trial to full membership.

Now we are talking about the second month billing, the rebill. It seems that three months is an industry standard, and those that rebill for four plus months are the gold that is sought.

Do not fret trying to come up with a formula until your paysite has a longer history with numbers to crunch.