Investment Yield (Growth Rate) Calculator - how well have your savings or investments performed?

Click here to launch the calculator

This calculator works out the annualised growth rate of an investment over a number of years based upon the original investment.

It can calculate the growth rate of single-premium investment (such as an investment bond) or a regular premium investment (such as a personal pension).

Please note that the calculator assumes that no withdrawals have been taken from the investment during the period in question.

While calculating a yield or growth rate for a single-premium investment is relatively straightforward, calculating an average growth rate based on a regular monthly contribution is more difficult. In effect it is more of a very close approximation.

For instance, if you were to pay £50 per month into a savings plan for ten years and at year ten it was worth £10,000, in order to calculate the true growth rate exactly, you would need to calculate the number of units purchased each month, then track the growth of those specific units for the remainder of the term. This would effectively entail a polynomial order of 120 separate calculations to solve.

Also you would need accurate details of each payment, and assuming you actually had all the information, it would still be a time-consuming task. Therefore, if this is not possible, the alternative method is to use an iterative approach, incorporating the Newton-Raphson root-finding method (similar to methods used in Excel functions such as RATE). This is the method used by this calculator.

The figures projected by the calculator are only for guidance purposes, and are by no means guaranteed.

Recent Financial Topics

Readers are using the small claims court to win their cash back. It comes after we reported how Pam Watts won £2,112 from British Airways after it cancelled her return flight without telling her.

Can't get a refund? Take stubborn companies to court!
27/10/2020 08:37 PM

After my husband died, I received part of his pension. Before this, my pensions were very small, so I had not paid tax since I retired. I have now received a number of demands from the taxman.

ASK TONY: Why is my pension tax bill riddle so difficult to solve?
27/10/2020 08:37 PM

From December, NS&I is phasing out posting warrants - a type of cheque - to winners. It instead wants bondholders to provide bank details so it can pay the money into their account.

Prize problem for Premium Bond holders without email
27/10/2020 08:37 PM