Quick answer
The Compound Interest Calculator shows how savings grow with compound interest and monthly contributions. How it works: FV = start × (1 + r)^m + monthly × ((1 + r)^m − 1) ÷ r; r = annual rate ÷ 12, m = months. For example, with starting amount of $5000, monthly contribution of $300, and annual return of 6 %, the future value is $155,163.29.
How to use the Compound Interest Calculator
- Enter starting amount.
- Enter monthly contribution.
- Enter annual return.
- Enter years.
- Read future value and the breakdown. Use Share to send the exact numbers, or Print to save a PDF.
How it's calculated
- FV = start × (1 + r)^m + monthly × ((1 + r)^m − 1) ÷ r
- r = annual rate ÷ 12, m = months
Worked example
With starting amount of $5000, monthly contribution of $300, annual return of 6 %, and years of 20:
Future value: $155,163.29. You put in: $77,000.00.
Questions people ask
Is the return guaranteed?
No. Investment returns vary year to year. Use a conservative rate for planning.