How It Works
ROI measures the percentage return relative to the original investment cost.
ROI = (Final Value − Initial Investment) / Initial Investment × 100 | Annualized: (FV/IV)^(1/years) − 1
- Net gain is the absolute dollar difference between final value and initial investment.
- Annualized ROI (also called CAGR — Compound Annual Growth Rate) converts the total return into an equivalent per-year rate, making it comparable across investments held for different periods.
- Annualized ROI uses the formula (FV/IV)^(1/n) − 1, where n is the number of years.
Worked Example
You invest $10,000 in a stock portfolio. After 3 years, the portfolio is worth $14,500.
Initial Investment
$10,000
Annualized ROI (CAGR)
+13.19%
A 45% total return over 3 years works out to about a 13.19% annualized return — a strong result, though every investment carries risk and past returns never guarantee future ones.
Understanding Return on Investment (ROI)
What ROI measures
Return on investment (ROI) tells you how much you gained or lost relative to what you put in, as a percentage. It is the simplest, most universal way to judge whether an investment, purchase, or business decision paid off: net gain divided by cost.
Because it is a ratio, ROI lets you compare very different things on the same scale — a stock trade, a rental property, a marketing campaign, or a piece of equipment can all be measured in the same percentage terms.
Total ROI vs annualized ROI (CAGR)
Total ROI ignores time: a 45% return is 45% whether it took one year or ten. That makes it misleading when comparing investments held for different periods. Annualized ROI — the compound annual growth rate (CAGR) — fixes this by expressing the return as a steady per-year rate.
Always compare investments on an annualized basis. A 45% return over three years (about 13% a year) is very different from 45% over ten years (under 4% a year), even though the total ROI is identical.
Gross vs net: fees, taxes, and income
A headline ROI is only honest if the numbers are complete. For total return, include income such as dividends, interest, or rent in the final value. For a true net result, subtract fees, commissions, and taxes — they can turn a good-looking gross return into a mediocre net one.
When comparing two options, make sure both are measured the same way: either both gross or both net, with the same treatment of income and costs.
What ROI does not tell you
ROI says nothing about risk. A 20% return from a volatile bet is not the same as 20% from something stable, even though the number is identical. It also says nothing about how much money was at work or for how long, unless you annualize it.
Use ROI as one input among several — alongside risk, liquidity, effort, and your own goals — rather than as the only score that matters.
ROI vs IRR for multiple cash flows
Simple ROI assumes one amount in and one amount out. Real investments often involve several contributions and withdrawals at different times. For those, the internal rate of return (IRR) is the right tool, because it accounts for the timing of every cash flow.
If your situation is a single lump sum that grew to a single final value, ROI and its annualized form are perfect. If money moved in and out repeatedly, reach for IRR or net present value instead.
Common mistakes
The frequent errors are comparing total ROIs across different time spans, forgetting to include income or subtract costs, and treating a high ROI as proof of a good decision regardless of risk. Another is reading past ROI as a forecast — it describes what happened, not what will.
This calculator is an educational tool for comparing outcomes. It is not investment advice, and past returns never guarantee future results.
Sources & References
Figures on this page are checked against primary, authoritative sources. Links open in a new tab.