Interest can earn interest
More frequent compounding slightly increases the future value when the nominal annual rate is the same.
Money & growth
Compound Interest Calculator
Estimate how savings or investments can grow over time with compound interest and optional monthly contributions.
Future value
$0Total contributed$0
Interest earned$0
See how time, rate, and contributions interact
Compound growth is sensitive to both the interest rate and the time invested. Regular contributions can make an even larger difference over long periods.
Compound interest formula
For an initial principal, the core formula is A = P(1 + r/n)nt, where P is the starting amount, r the annual rate, n the number of compounding periods per year, and t the number of years.
Regular deposits can dominate growth
Monthly contributions are modeled as deposits made at the end of each month.
Frequently asked questions
What is compound interest?
It is interest calculated on the original principal plus accumulated interest from earlier periods.
Does this include monthly contributions?
Yes. Set the contribution to zero if you only want growth of the starting principal.