A big thank you for the reply and its similar to the formulas that I have stared at and through for most of today:-

"For this simple type of loan you have to solve the following equation:

Where MR is the monthly repayment, N the number of periods, r the

percentage APR, and 12 the number of periods in a year."

The bad news is that I do not have the MR and want to calculate r.

But thank you anyway, was almost saved :-)