Your inputs
This calculator provides estimates for educational purposes and does not constitute financial advice.
How compound interest works
Compound interest means interest is added to your balance and future interest can then be earned on both your original money and previous interest.
A = P(1 + r/n)^(nt)
Where A is the future value, P is the starting amount, r is the annual rate as a decimal, n is the number of compounding periods per year, and t is the number of years.
Worked example
If you start with £10,000, earn 5% a year, contribute £200 each month and leave the money invested for 10 years, the calculator estimates the future value using the assumptions you enter above.
Frequently asked questions
Does this guarantee investment returns?
No. It is an estimate based on the rate you enter. Real investment returns can rise or fall and may include fees, taxes or losses.
What does compounding frequency mean?
It describes how often interest is added to the balance. More frequent compounding can slightly increase the calculated future value when all other inputs are unchanged.
Are monthly contributions included?
Yes. This calculator adds the monthly contribution at the end of each month and applies growth over time.