Principle How much could I borrow based on a regular repayment I can afford to pay? Repayment If I borrowed so much for a certain period at a specified interest rate, what would my regular repayments be? Rate What is the interest rate for a loan repaid over a specified period? Period If I borrowed so much with specified repayments at a specified interest rate, how long would it take to pay the loan off? Calculations involving compound interest can be complex and a number of factors can affect the overall computation. This calculator is designed to give you a close approximation of what you might expect on loans which are repaid by regular instalments which do not change throughout the period of the loan and the interest rate is fixed.