Growth and return formulas, plus a simulator built on real market history.
The Investment Simulator runs your numbers against a stock or index's actual historical daily prices, so the result reflects real market ups and downs. The Investment Growth Calculator instead projects forward from one assumed annual return rate you choose, useful for planning at a steady assumed rate rather than replaying real history.
CAGR (compound annual growth rate) is the single steady yearly rate that would take a starting value to an ending value over a period, accounting for compounding. A simple average of yearly returns ignores compounding and can overstate real growth, especially in volatile years.
The Rule of 72 divides 72 by the annual rate for a quick mental estimate. The exact formula uses a logarithm and is more accurate, especially at higher rates. The Rule of 72 tool on this site shows both side by side.