Compound Interest Calculator

About the Compound Interest Calculator

Compound interest means you earn returns on your earlier returns, so savings can grow faster over time. This calculator shows how a starting amount plus regular monthly deposits could grow at a yearly return you choose.

How to use the Compound Interest Calculator

1. Enter your Starting amount.
2. Enter the Monthly deposit you plan to add.
3. Enter the yearly Return as a percentage and the number of Years.
4. Read the final amount, the total you deposited and the interest earned.

Good to know

• The calculator compounds monthly and assumes each deposit is made at the end of the month.
• Small changes in the return rate or the number of years make a large difference over a long time. Try a few values to see the effect.
• The result is an illustration, not a promise. Real investments rise and fall, and fees and taxes reduce what you keep.

Frequently asked questions

What is the formula for compound interest?

For a lump sum, the final amount is the starting amount multiplied by (1 + rate per period) raised to the number of periods. Monthly deposits are added using the future value of an annuity formula.

Can I use it for a bank savings account?

Yes, if you enter the account's yearly rate. Check how often your bank actually pays interest, because that can differ from monthly.

Is this financial advice?

No. It is a maths tool for planning. Speak to a qualified adviser before making investment decisions.