Interest 4 is a nifty iPhone app to help you with your interest or loan calculations. It’s a pretty straightforward app that’s meant to take the pain out of complex calculations.
Interest 4 helps you with four different types of calculations — Simple Interest, Compound Interest, Equal Total Payments and Equal Principal Payments. You can either use the Hamburner button located at the top right of the screen to toggle between these four modes or just swipe to the left or right. The app uses a simple iOS 7-style UI, with different background color for each mode. Simple & Compound Interest calculation inputs are fairly easy to understand, but the other two modes have a ‘more’ button to show you additional data.