What Is ROI (Return on Investment)?
Return on Investment (ROI) is a simple, universally understood metric that measures the net profit of an investment relative to its total cost. The formula is: ROI = (Net Profit ÷ Total Cost Basis) × 100. A 50% ROI means you earned 50 cents for every dollar invested — regardless of how long it took to achieve.
ROI Formula
ROI = ((Final Value − Total Cost) ÷ Total Cost) × 100
Total Cost = Initial Investment + Fees + Taxes + Maintenance Costs. Always include all costs for an accurate picture of real profitability.
ROI vs CAGR — The Critical Difference
ROI and CAGR both measure investment performance, but answer different questions. ROI tells you the total return; CAGR tells you the annualized rate that produced it. This distinction is critical when comparing investments held for different time periods.
| ROI | CAGR | |
|---|---|---|
| What it measures | Total return over the full period | Annualized (per year) return rate |
| Time-adjusted? | No — ignores duration | Yes — accounts for holding period |
| Best used for | Quick profit check | Comparing investments of different durations |
| Formula | (Profit ÷ Cost) × 100 | (FV ÷ IV)^(1/n) − 1 |
| Example | $50K profit on $100K = 50% ROI | 50% ROI over 5 years = 8.45% CAGR |
Factors Affecting Investment Returns
Inflation
If your 10% ROI is achieved when inflation is 6%, your real purchasing power gain is only ~3.77%. Always calculate real returns.
Fees & Expenses
A 1% annual management fee seems small but reduces a 20-year 10% CAGR investment by ~15% of final value. Keep costs minimal.
Taxes
Capital gains taxes directly reduce realized profits. Long-term capital gains are taxed at lower rates than short-term — holding period matters.
Time Horizon
Compounding is most powerful over long periods. The same 10% CAGR turns $10K into $67K over 20 years but only $16K over 5 years.
Market Risk
Higher potential returns come with higher volatility. Stocks have outperformed over long periods but can drop 30-50% in downturns.
Reinvestment
CAGR assumes profits are reinvested. If dividends or distributions are withdrawn rather than compounded, actual returns will be lower.