Thanks for the reply, Stephen. There are basically four options people can choose. In order of popularity, these are:
- Borrow X, repay (Y+interest) each week e.g. Borrow £200, repay £5 + interest per week.
- Borrow X, repay Y (including interest) per month e.g. Borrow £500, repay £50 total principal and interest each month
- Borrow X, repay (Y+interest) per month
- Borrow X, repay Y (including interest) per week
In 1 and 3, the period of the loan is easy to calculate - X/Y weeks/months. In 2 and 4, it's more problematic. The interest rate is 1% per 30 day month, APR 12.68%.
The purpose of having the calculator on the website is to give people an indication of how much interest they would pay over the period of a loan, to show how affordable these rates are by comparison with others. Even having a calculator that only deals with option 1 would be a significant improvement on what we have now. :)