Principle How much would I have in so many years time if I saved regular amounts? Payments If I wanted so much in so many years time, how much should I save regularly? Rate If by saving regular amounts, I was promised a certain figure in so many years time, what is the net interest rate? Period If I could afford to save a regular amount, how long would it take to save a specified amount? Calculations involving compound interest can be complex and a number of factors can affect the overall computation. There are many ways in which you can save: a lump sum; a lump sum follwed by regular amounts; regular amounts; variable amounts - plus you may even make some withdrawals during the period etc. This calculator is designed to give you a close approximation of what you might expect if you save a regular amount. This amount must remain the same over the period and the net interest rate fixed.