Compound Interest Calculator
See how compound interest can help your money grow over time. Enter your initial investment, contribution amount, interest rate, and time horizon.
The amount you start with (your initial deposit or principal).
The expected annual interest rate or rate of return.
How long you plan to leave the money invested.
Optional regular contribution (e.g., monthly deposits into savings).
How often you make regular contributions.
How often interest is calculated and added to your account.
This calculator shows how compound interest works - the phenomenon of earning interest on your interest. See how different contribution amounts, interest rates, and time periods affect your final balance.
How It Works
Compound Interest Formula
A = P(1 + r/n)^(nt) + PMT x [((1 + r/n)^(nt) - 1) / (r/n)]The future value equals the compounded principal plus compounded regular contributions.
A is the final amount (future value)
P is the principal (initial investment)
PMT is the regular contribution amount
r is the annual interest rate (as a decimal)
n is the number of times interest is compounded per year
t is the number of years
Important Notes:
- •This calculator assumes compound interest is added at regular intervals based on the compounding frequency.
- •Contributions are assumed to be made at the end of each period.
- •Actual returns may vary and are not guaranteed - this calculator uses hypothetical returns.
Worked Example
Starting with $10,000 and adding $500 monthly at 7% annual interest for 20 years.
Inputs:
- principal:10,000
- annual Interest Rate:7
- years:20
- contribution Amount:500
- contribution Frequency:monthly
- compounding Frequency:monthly
Result:
The final balance would be approximately $325,525. You contributed $130,000 total, meaning compound interest earned you approximately $195,525.
Who Is This Calculator For?
- investors
- savers
- retirement planners
- students