Compound Interest Calculator
Calculate how your investment grows over time with compound interest and regular contributions.
Enter investment details and click Calculate
About Compound Interest
Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. It is the foundation of long-term wealth creation.
Formula
A = Final amount | P = Principal | r = Annual rate (decimal)
n = Compounding periods/year | t = Years | PMT = Monthly contribution
FAQs
Compounding means your interest earns interest. Over time, this creates exponential growth — even a small return can produce significant wealth over decades. The earlier you start investing, the more powerful compounding becomes.
More frequent compounding yields slightly more interest. Daily compounding earns slightly more than monthly, which earns more than annual. However, the difference is small unless the amount is very large or the rate is high.
The Rule of 72 is a quick way to estimate how long it takes to double an investment. Divide 72 by the annual interest rate. For example, at 8% annual return, your money doubles in approximately 72/8 = 9 years.