Compound Interest & Wealth Growth Engine
Model exponential growth. Calculate future portfolio balance, total periodic contributions, compound interest earned, and observe your doubling milestones.
A = P(1+r/n)^(nt) + PMT×S_n
Contribution & Growth Assumptions
help Frequently Asked Questions
What is compound interest and how does it work?
Compound interest is interest calculated on your initial principal plus all the accumulated interest from previous periods. Often called "interest on interest", it causes your wealth to grow exponentially over time rather than linearly.
What is the mathematical compound interest formula?
The standard compound interest formula is A = P(1 + r/n)^(nt), where A is the future value, P is initial principal, r is the annual interest rate (decimal), n is compounding frequency per year, and t is time in years.
What is the Rule of 72 in investing?
The Rule of 72 is a mental shortcut to estimate how many years it takes for your investment to double. Divide 72 by your expected annual rate of return. For example, at an 8% return, your money doubles approximately every 9 years (72 / 8 = 9).
Does compounding frequency make a big difference?
Yes. Daily compounding yields slightly more than monthly or annual compounding because your earned interest starts generating its own returns sooner. Over 20–30 years, frequent compounding generates substantial additional wealth.