How to calculate ROI
Return on investment (ROI) tells you how much profit you made relative to what you spent. The formula is ROI = (Net profit ÷ Cost) × 100, where net profit is your final value minus your cost. A 50% ROI means you earned half of your original investment as profit on top of getting your money back.
Limitations
Simple ROI ignores time. A 50% return over one year is very different from 50% over ten years. For investments held over different periods, use the annualized return (also shown here when you enter a holding period). For a full multi-year model with contributions, try the compound interest calculator.
For investing the funds behind your ROI calculation, these brokerages offer low-fee accounts.