Prepayment Penalty Wording

[John K.]

I should start by saying never intended to pre-pay any cheap debt with how low rates currently are.  But now I'm just curious about some wording as the thought crossed my mind the other day.  

As I was re-reading some of my loan documents, I re-read the pre-payment penalty on a loan and it's worded after the percentages:  "of the principal balance then outstanding shall be paid to the bank" - what is the percent prepayment penalty based on?  Is it based on the loan balance remaining?  So if the loan is 200k, and I pay 10k then the outstanding balance would be 190k, so would the penalty be  X% of 190k?