About the ROI Calculator
The ROI Calculator computes total return on investment ((gain − cost) ÷ cost) plus the annualized rate when you enter a holding period — the only fair way to compare investments of different lengths.
The constant yearly rate that would produce the same total result: (end/start)^(1/years) − 1. A 50% gain over 5 years is ~8.4% p.a., not 10%.