Interest Rate and Compound Interest Calculator / Solver.

Click here to launch the calculator

Use this calculator to work out Annual Percentage Rates, or perform calculations relating to loans and interest rates.

(Requires Flash Player 7 or higher).

You can use this calculator / solver to:

1. Work out the Annual Percentage Rate (APR) from a monthly rate of interest, or vice versa. (You can use change the interest period from monthly to daily, weekly, quarterly or half-yearly).

2. Work out the factors in Compound Interest Loan calculations, based upon three of the known factors. Therefore, you need to enter three of the following values:

Initial Value (i.e. the amount of money that is borrowed)
Interest Rate
The duration / length of the loan (in years)
The total amount of money that is repaid (i.e. initial value + interest)

Points to be aware of:

All results are rounded down to 4 decimal places, and this should be sufficient for most purposes. You can round this down further yourself (i.e. to 2 decimal places).

When enter 'part years' in the loan calculator (i.e. 7 years and 10 months), these need to be added as a fraction.

i.e. To work out 10 months as a decimal fraction, divide 10 by 12, and this gives the result 0.8 - therefore, enter 7.8 into the calculator. Any results calculated this way will also show the years and months underneath.

The figures projected by the calculator are only for guidance purposes - whilst we aim to ensure the accuracy of our calculators, we can take no responsibility for the usage made of the calculations generated on this site.

Recent Financial Topics

Filling out the Power of Attorney forms is possible without expert guidance. But these are some of the most common pitfalls.

How to complete Power of Attorney forms without expert help - and the blunders to avoid to save you money and delays... and stop your application being rejected
07/06/2026 12:08 PM

A growing number of adverts pose as impartial advice without clearly saying they are promoting a business, and fail to make clear you can claim for free, says FCA

Beware 'money tips' adverts about motoring finance that promote claims management firms, says FCA
07/06/2026 11:01 AM

Delays have now been purposely driven up by health service bosses intent on balancing short-term budgets.

I can cut the wait time for your eye operation - if only the NHS would let me, says SpaMedica boss
07/06/2026 09:43 AM