ROI โ return on investment โ is the most quoted number in investing and business. It answers one question: did this investment make money, and how much? But like any good metric, it can mislead when used alone. Here's how to calculate it right.
What Is ROI?
ROI measures the gain or loss generated on an investment relative to its cost. Because it's a ratio, it lets you compare very different investments โ a $500 side project and a $50,000 rental โ on the same scale.
The ROI Formula
ROI % = ((Final Value โ Initial Cost) รท Initial Cost) ร 100
Where:
- Final Value = what the investment is worth now (including any income it produced)
- Initial Cost = everything you put in (purchase price, fees, repairs)
Example: Buying a Stock
You buy $10,000 of a stock and later sell it for $12,500:
ROI = (($12,500 โ $10,000) รท $10,000) ร 100 = 25%
Add $300 of dividends collected along the way, and the final value becomes $12,800:
ROI = (($12,800 โ $10,000) รท $10,000) ร 100 = 28%
Annualized ROI: The Missing Comparison
A 25% ROI sounds great โ until you learn it took 6 years. To compare investments held for different lengths of time, annualize the return:
Annualized ROI = ((1 + Total ROI)^(1 รท Years)) โ 1
| Investment | Total ROI | Holding Period | Annualized ROI |
|---|---|---|---|
| A | 30% | 2 years | 14.0% |
| B | 40% | 5 years | 7.0% |
Investment A's 30% beats B's 40% on an annualized basis โ because it delivered its return in less than half the time.
ROI vs Other Metrics
ROI ignores time and timing of cash flows. That's where richer metrics come in:
| Metric | What it answers | Best for |
|---|---|---|
| ROI | How much did I make? | Quick comparisons |
| Annualized ROI | How fast did I make it? | Comparing time frames |
| Payback period | When do I get my money back? | Risk-sensitive decisions |
| Net Present Value (NPV) | Is it worth more than the same cash elsewhere? | Long projects |
| IRR | What annual rate does the project earn? | Capital budgeting |
A marketing campaign might show a 300% ROI while an equipment purchase shows 15% โ but the campaign's cash flows arrive in months and the equipment's over a decade. Same metric, very different risk.
What Does a Good ROI Look Like?
Typical long-run reference points (before tax):
| Investment | Typical annualized ROI | Risk |
|---|---|---|
| High-yield savings / CDs | 4โ5% | Very low |
| Bonds | 3โ6% | Lowโmoderate |
| Stock market (long-run) | ~7โ10% | Moderate |
| Rental property | 5โ12% | Moderate |
| Small business | 10โ25% | High |
| Early-stage venture | 20%+ (but many failures) | Very high |
Higher expected returns always come with higher risk โ and with more volatile outcomes.
Common ROI Mistakes
โ Ignoring costs: A $200 profit on a $1,000 investment is 20%; with $100 of fees, it drops to 10%
โ Ignoring time: Comparing a 3-month 10% return to a 3-year 10% return as if they're equal
โ Ignoring taxes: A 20% gross return may be 15% after taxes
โ Ignoring risk: Past ROI tells you little about the future โ especially on volatile assets
๐ก Pro Tip: Always ask 'ROI over what period?' When someone quotes a return, annualize it first. A '200% return' from 8 years ago is about 14.7% per year โ impressive, but a very different number than it sounds.
Try Our ROI Calculator
Our ROI Calculator helps you:
- Calculate ROI instantly from cost, final value, and income
- See annualized ROI for any holding period
- Compare multiple investments side by side
- Understand what your money is doing over time
Related Reading
- Investment Calculator: Project Your Portfolio Growth
- Compound Interest: How Your Money Grows Exponentially
- Net Present Value (NPV): How to Value a Project
- Present Value: What Future Money Is Worth Today
- Profit Margin: Margin vs Markup Explained Simply
- CAGR Calculator: Compound Annual Growth Rate Explained Simply
*Measure your returns honestly with our free ROI Calculator.*
