See how savings or investments grow when interest earns interest. Add regular monthly deposits and choose how often interest compounds.
How the compound interest calculator works
A = P(1 + r/n)^(nt), plus the future value of your monthly deposits. P is the starting balance, r the annual rate, n the compounding periods per year and t the number of years.
Example
Starting with $10,000, adding $200 a month at 7% compounded monthly for 15 years gives about $91,900. You contribute $46,000 and the remaining $45,900 or so is interest.
Frequently asked questions
What is compound interest?
Interest calculated on both your original balance and the interest already earned, so growth speeds up over time.
Does compounding more often help?
Slightly. Daily compounding earns a little more than annual compounding at the same rate, but the rate and time matter far more.
Is the result guaranteed?
No. It assumes a constant rate. Real returns vary, so treat the result as an estimate.