Return on Investment (ROI)
$$\text{ROI} = \frac{\text{Final Value} - \text{Initial Cost}}{\text{Initial Cost}} \times 100$$
What is Return on Investment (ROI)?
Return on Investment (ROI) measures how much an investment gains or loses relative to its cost. It is calculated by subtracting the initial cost from the final value, dividing by the initial cost, and multiplying by 100 to express the result as a percentage. A positive ROI means the investment was profitable; a negative ROI means it lost money.
ROI's power lies in its universality: it reduces any investment — a stock purchase, a marketing campaign, a factory machine, or a new hire — to a single comparable percentage. A marketing campaign that cost $10,000 and generated $40,000 in attributable revenue has an ROI of 300%, making it directly comparable to a $50,000 equipment upgrade that saves $15,000 per year (30% annual ROI).
The main limitation of simple ROI is that it ignores time. An ROI of 50% is excellent in one year but mediocre over a decade. For multi-year investments, CAGR (Compound Annual Growth Rate) is the more useful companion metric, as it converts total ROI into an annualised rate that accounts for the time value of money.
When to use Return on Investment (ROI)
Use ROI as a first-pass filter to compare mutually exclusive investments or marketing channels. Pair it with CAGR for any investment spanning more than one year. Do not use standalone ROI to compare investments with very different time horizons without also computing the annualised rate.
Worked examples
| Investment | Initial Cost | Final Value | Net Return | ROI |
|---|---|---|---|---|
| Stock purchase | $10,000 | $14,500 | $4,500 | 45% |
| Marketing campaign | $5,000 | $18,000 | $13,000 | 260% |
| Equipment upgrade | $80,000 | $95,000 | $15,000 | 18.75% |
| Failed product launch | $25,000 | $12,000 | −$13,000 | −52% |
Common pitfalls
ROI is easily manipulated by choosing what counts as "cost" or "return." A marketing ROI calculation that includes only ad spend but ignores agency fees, creative production, and staff time will be significantly inflated. Always use fully-loaded costs. For capital investments, also compare ROI against the company's weighted average cost of capital (WACC) — a 10% ROI is not attractive if the company's cost of capital is 12%.
Frequently asked questions
What is a good ROI?
There is no universal benchmark — it depends on the investment type, risk level, and time horizon. Stock market investors historically target 7–10% annualised (inflation-adjusted). Marketing campaigns are often evaluated against a minimum 3:1 return ($3 return per $1 spent, i.e., 200% ROI). The only valid comparison is against the opportunity cost: what else could the capital have earned?
What is the difference between ROI and CAGR?
ROI measures total return over the full investment period regardless of length. CAGR converts that total return into an equivalent annual rate, enabling fair comparison across investments held for different periods. A 100% ROI over 2 years equals a CAGR of approximately 41.4%; the same 100% ROI over 5 years equals a CAGR of 14.9%.
How does ROI differ from ROE?
ROI is a general-purpose investment return metric that applies to any asset. ROE (Return on Equity) is a specific corporate finance metric comparing net income to shareholders' equity — it measures management's efficiency in using owner capital. A company's overall ROE informs investors; project-level ROI informs internal capital allocation decisions.