Frequently Asked Questions & Formulas
What is the formula for compound interest with regular deposits?
The formula is FV = P(1 + r/n)^(nt) + PMT * [ ((1 + r/n)^(nt) - 1) / (r/n) ], where P is initial principal, PMT is periodic payment, r is annual rate, n is compounding periods per year, and t is years.
What is the Rule of 72?
The Rule of 72 is a mental shortcut to estimate how many years it takes for an investment to double: Divide 72 by the expected annual interest rate (e.g., at 8% return, 72 / 8 = 9 years to double).
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