ROI Calculator
Calculate your return on investment, annualized CAGR, and IRR with cash flows. Compare two investments side by side with risk-adjusted analysis and benchmark against the S&P 500.
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How to Use This Calculator
Simple ROI tab
The default tab. Enter your initial investment, final value, and time period in years. The calculator shows total ROI, annualized ROI (CAGR), dollar gain, and benchmark comparisons against the S&P 500, HYSA, and inflation. Expand "More options" to deduct fees or adjust for inflation.
With Cash Flows tab
Use this when you made periodic contributions or received periodic income (like rental income or dividends). Enter the cash flow amount and frequency, then the final value. The calculator computes IRR (Internal Rate of Return) using a bisection method — the true money-weighted return accounting for timing of all cash flows.
Compare Investments tab
Put two investments side by side. Enter names, final values, and time periods. Expand "More options" to add annual fees and risk levels. The calculator provides a risk-adjusted comparison so you can see whether higher returns justify higher risk.
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Every input is encoded in the URL. Click Share to send your exact scenario to a partner, advisor, or colleague.
The Formulas
Three core formulas power this calculator:
CAGR = (Final Value / Initial Investment)^(1/n) - 1
where n = number of years
Rule of 72: Years to Double = 72 / Annual Return Rate
Total ROI is simple and intuitive but ignores time. A 50% return over 3 years is very different from 50% over 30 years.
CAGR (Compound Annual Growth Rate) normalizes for time by calculating the steady annual rate that would take you from initial to final value. This is the standard for comparing investments of different durations.
IRR (Internal Rate of Return) extends CAGR to handle irregular cash flows — contributions, withdrawals, income. It finds the discount rate that makes the net present value of all cash flows equal to zero.
The Rule of 72 is a quick mental math shortcut: divide 72 by your annual return to estimate how many years it takes to double your money.
Example
Sarah — Index Fund Investor, 3-Year Horizon
Sarah invested $10,000 in an S&P 500 index fund 3 years ago. Today it is worth $15,000.
Simple ROI
Total ROI = ($15,000 - $10,000) / $10,000 = 50%. Annualized ROI (CAGR) = (15,000/10,000)^(1/3) - 1 = 14.47%. After 3% inflation, real return is approximately 11.2%. At this rate, her money doubles every 5 years (72 / 14.47).
Benchmark comparison
Sarah's return of 14.47% annualized outperformed the S&P 500 long-term average by over 4 percentage points. Over these 3 years, the market was particularly strong.