Overview
What Is Compound Interest?
Compound interest is interest calculated on both your initial principal and the accumulated interest from previous periods - money earning money on itself.
See how your investment grows with compound interest.
Compound interest is interest calculated on both your initial principal and the accumulated interest from previous periods - money earning money on itself.
Useful for projecting investment growth, retirement planning, or understanding how compounding frequency affects returns.
Input your starting investment amount.
Input the annual interest rate.
Input how long you'll invest and how often interest compounds.
The result updates automatically.
A = P(1 + r/n)^(nt), where P is principal, r is rate, n is compounding frequency, and t is time in years.
Simple interest only accrues on the principal; compound interest accrues on principal plus previously earned interest.
It has a modest effect - more frequent compounding yields slightly more than less frequent, at the same stated rate.
This varies by investment type - historical stock market averages are often cited around 7-10% annually, though actual results vary.
This tool is designed for investment growth. For loan payments, use the loan calculator instead.
No, this shows gross growth before any taxes on investment gains.
This calculator uses a one-time principal. For regular contributions, see the savings calculator.
With a positive interest rate, yes - your balance grows over time.
Roughly, divide 72 by your interest rate for an estimate (the 'Rule of 72').
Yes, completely free with no sign-up required.