In-depth
What Is ROI and How to Calculate It
ROI (Return on Investment) is one of the most widely used financial indicators for evaluating the efficiency and profitability of an investment. It expresses as a percentage the gain or loss generated relative to the capital initially invested, allowing for quick comparison of different investment opportunities.
The ROI Formula
The basic ROI formula is simple and straightforward:
ROI = ((Gain – Investment Cost) / Investment Cost) × 100
Or, equivalently:
ROI = (Net Profit / Investment Cost) × 100
Practical Example
Suppose you purchase stocks worth €10,000 and sell them after a period for €13,500:
- Net profit: 13,500 – 10,000 = €3,500
- ROI: (3,500 / 10,000) × 100 = 35%
An ROI of 35% means that for every euro invested, you earned €0.35 in profit.
Annualized ROI
The basic ROI does not account for the time factor. A 30% ROI in 6 months is very different from a 30% ROI over 5 years. To compare investments with different time horizons, the annualized ROI is used:
Annualized ROI = ((1 + ROI)^(1/n) – 1) × 100
where n is the number of years of the investment.
| Investment | Total ROI | Duration | Annualized ROI |
|---|---|---|---|
| Tech stocks | 45% | 3 years | 13.2% |
| Real estate | 60% | 7 years | 6.9% |
| Bonds | 12% | 2 years | 5.8% |
| Startup | 200% | 5 years | 24.6% |
As shown, the real estate investment with a total ROI of 60% is less efficient on an annual basis than the stocks with a 45% ROI, because the capital was tied up for a longer period.
How to Interpret ROI
- Positive ROI: the investment generated a profit
- ROI = 0%: break-even, no gain or loss
- Negative ROI: the investment produced a loss
There is no universally "good" value: it depends on the sector, the level of risk, and the time horizon. Generally, an annualized ROI above 7–10% is considered positive for medium- to long-term investments.
Comparing Investments
ROI is particularly useful for comparing investment alternatives. If you have capital and can choose among different options, the annualized ROI helps identify the most efficient one at the same level of risk. However, it is essential to also consider other factors: liquidity, volatility, management costs, and taxation.
Limitations of ROI
While intuitive and easy to calculate, ROI has some important limitations:
- Does not consider risk: a high ROI might come from a very risky investment
- Does not include time (in the basic formula): it must be annualized for proper comparisons
- Does not account for inflation: a 3% ROI with 4% inflation is a real loss
- Ignores interim cash flows: dividends, coupons, or rents received during the period are not considered in the simple formula
- Depends on the definition of "cost": including or excluding commissions, taxes, and ancillary costs changes the result
For more comprehensive analysis, ROI is often paired with other indicators such as IRR (Internal Rate of Return), NPV (Net Present Value), or the Sharpe ratio, which incorporates risk.
How to Use the Calculator
Enter the amount invested and the final value (or the gain obtained). If you want to calculate the annualized ROI, also enter the investment duration. The calculator will return the percentage ROI, the net profit, and, if applicable, the annualized return for an immediate comparison between different opportunities.
