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About the Compound Interest Calculator
Find the future value of a deposit when interest is added to the balance at regular intervals. Compare compounding frequencies and see the effective annual rate and how long the money takes to double.
How to use it
- Enter the principal, the annual interest rate and the number of years.
- Pick how often interest is compounded.
- Read the final amount, interest earned, effective annual rate and doubling time.
Frequently asked questions
What is the compound interest formula?
A = P × (1 + r ÷ n)^(n × t), where P is the principal, r the annual rate as a decimal, n the compounding periods per year and t the number of years.
Why does more frequent compounding earn slightly more?
Interest is added sooner, so later interest is calculated on a slightly larger balance. The effective annual rate shows the true yearly growth.
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Results are estimates for general information. For financial, tax, medical or legal decisions, check with a qualified professional.