I have had many requests for a Visual Studio solution project with the APR code and unit tests in. I have open sourced the code and put it onto Codeplex to make it easy for you to access.
In this article I want to discuss Annual Percentage Rates (APR) and how you calculate them including some sample code. APR is a term you will see on several different lending products including loans, overdrafts, credit cards and mortgages. It is a legal requirement to show the APR on products where you borrow money, (certainly in the UK). The APR is meant to make it easier to make fairer comparisons of different products. To make things even more confusing there are 2 types of APR, Personal APR and Typical APR.
The APR is essentially how much your borrowing will cost over the period of an average year, over the term of your debt. It takes into account interest charged as well as any additional fees (such as arrangement fees, or annual fees) you’ll have to pay. It also considers the frequency with which interest is charged on your borrowing, as this as an impact on how much you will pay as well.