For calculating the percent for a period (ie. month) one can use the following formulae (here as C++ functions): Code: double PeriodPct(const double AdblStartCap, const double AdblEndCap, const double AdblPeriods) { // = (nthRoot(Kn/K0) - 1) * 100 return (pow(AdblEndCap / AdblStartCap, 1.0 / AdblPeriods) - 1.0) * 100.0; } double PeriodPct(double AdbPLpct, const double AdbPeriods) { const bool fNeg = AdbPLpct < 0.0; if (fNeg) AdbPLpct *= -1.0; double db = PeriodPct(100.0, 100.0 + AdbPLpct, AdbPeriods); if (fNeg) db *= -1.0; return db; } If one knows only the percent of x periods and x, then one can use the second function. Like K-Pia wrote, one can also first calculate the monthly pct, and then extrapolate to 12 months.
(Additional quiz) Someone started investing at 30 and now 80, with 5000 times now of the initial seed. (For example he made 5000*10K at 80, with seed of saved 10K at 30) What is the annual compounded rate?
499900% in 50 years...: when using periodic compounding: 18.571250487% p.a. when using continuous compounding: 17.034386383% p.a. Is that maybe good ole Warren Buffett? ;-) No, no Warren Buffet started investing as a kid...
300% in 6 months means you quadrupled your money. Quadruple it again, in the next 6 months, means you have x16, which is 1500%.
Continuous compounding is applicable ---- P at Tzero 300% at Tone = 4P Ttwo = exp ( 2 * ln(4) ) = 16P 16P is 1500% return