How to Calculate ROI: Formula, Annualized ROI and Examples

Return on investment (ROI) is the single most common metric used to decide whether spending money was worth it — yet it is routinely miscalculated or misread. This guide walks through the exact formula, shows how to annualize ROI so you can compare investments with different time horizons, and applies the math to marketing campaigns and real estate. Every formula comes with a fully worked numerical example.

The Basic ROI Formula

ROI measures the gain or loss on an investment relative to its cost. The formula is:

ROI = (Net Profit / Cost of Investment) × 100

Where Net Profit = Final Value − Cost of Investment.

Example: You buy equipment for $10,000 and sell the goods it produces for a net revenue of $13,500 after all operating costs. Net profit = $3,500.

ROI = (3,500 / 10,000) × 100 = 35%

A 35% ROI means every dollar invested returned $1.35. That number is meaningful only when you also know how long the investment ran — which is where annualized ROI comes in.

Annualized ROI: Comparing Investments on Equal Footing

A 35% ROI over 6 months is very different from 35% over 5 years. Annualized ROI — sometimes called Compound Annual Growth Rate (CAGR) — standardizes the return to a per-year basis:

Annualized ROI = [(1 + ROI)^(1/n) − 1] × 100

where n is the holding period in years.

Example A — short hold: ROI of 35% over 0.5 years (6 months).

Annualized ROI = [(1.35)^(1/0.5) − 1] × 100 = [(1.35)^2 − 1] × 100 = 82.25%

Example B — long hold: ROI of 35% over 5 years.

Annualized ROI = [(1.35)^(1/5) − 1] × 100 ≈ 6.2%

Same raw ROI, radically different annualized returns. Always annualize before comparing alternatives.

Side-by-Side Comparison: Four Investments

Investment	Cost	Final Value	Hold Period	Raw ROI	Annualized ROI
Stock purchase	$5,000	$6,750	2 years	35%	16.2%
Rental property	$80,000	$108,000	5 years	35%	6.2%
Marketing campaign	$2,000	$2,700	3 months (0.25 yr)	35%	170.9%
Business equipment	$10,000	$13,500	6 months (0.5 yr)	35%	82.3%

All four show the same 35% raw ROI, yet the marketing campaign's annualized figure towers over the rest. This is why a 3-month campaign ROI should never be directly compared to a 5-year property ROI without annualizing first.

Marketing ROI

Marketing ROI isolates the revenue attributable to a specific campaign minus campaign costs:

Marketing ROI = ((Revenue from Campaign − Campaign Cost) / Campaign Cost) × 100

Example: A paid-search campaign costs $4,000 and generates $14,000 in attributed revenue. The gross margin on those sales is 50%, so the profit contribution is $7,000.

Using gross profit: ($7,000 − $4,000) / $4,000 × 100 = 75%
Using raw revenue (common but inflated): ($14,000 − $4,000) / $4,000 × 100 = 250%

The difference is significant. Always use gross profit, not revenue, when calculating marketing ROI — otherwise you are ignoring the cost of goods sold and the number is misleading. A benchmark to know: the widely-cited rule of thumb in B2C marketing is that a 5:1 revenue-to-spend ratio (400% ROI on revenue) is considered strong; anything below 2:1 typically means the channel is losing money once COGS is factored in.

Real Estate ROI

Real estate ROI can be measured two ways: as a simple return on the total purchase price, or — more usefully — as a cash-on-cash return on the actual cash you invested (down payment + closing costs).

Simple ROI example: You buy a rental property for $200,000. After 3 years it sells for $230,000 and you collected $18,000 in net rental income (after maintenance, taxes, insurance). Total gain = $48,000.

ROI = (48,000 / 200,000) × 100 = 24% over 3 years → Annualized ≈ 7.5%

Cash-on-cash ROI (leveraged view): You put $40,000 down (20%) and financed the rest. Your annual net cash flow after mortgage payments is $3,200.

Cash-on-Cash ROI = (3,200 / 40,000) × 100 = 8% per year

Leverage amplifies ROI dramatically — which cuts both ways. A drop in property value or a vacancy period hits your small cash investment hard.

Common Mistakes That Distort ROI

Ignoring time. Comparing a 2-year ROI to a 10-year ROI without annualizing is one of the most frequent errors in investment analysis. Always convert to an annualized figure first.
Using revenue instead of profit. Especially common in marketing. Revenue minus cost of goods sold gives gross profit; that is the correct numerator.
Forgetting opportunity cost. An 8% annual ROI sounds fine until you realize the S&P 500 has historically averaged roughly 10% annually (pre-tax). ROI should be weighed against what else you could have done with the capital.
Omitting hidden costs. Real estate investors frequently omit vacancy rates, property management fees, and capital expenditures. Business owners forget employee time. Marketing teams miss agency overhead. Every cost must be in the denominator.
Treating sunk costs as future investments. Money already spent is gone. ROI on a future decision should only include forward-looking costs and returns.
Confusing ROI with IRR. ROI is a single-period snapshot. Internal Rate of Return (IRR) handles investments with multiple cash flows over time and is the more rigorous tool for complex projects.

Quick Reference: Which ROI Formula to Use

Scenario	Best Formula	Key Nuance
Single-period investment	Basic ROI = Net Profit / Cost	State the time period explicitly
Comparing across time horizons	Annualized ROI (CAGR)	Use compounding, not simple division
Marketing / advertising	ROI using gross profit contribution	Never use top-line revenue alone
Rental property (leveraged)	Cash-on-cash return	Use actual cash invested, not purchase price
Multi-year project with cash flows	IRR	ROI alone is insufficient here

Questions fréquentes

What is a good ROI percentage?+

It depends entirely on the asset class and time frame. For public equities, 8–10% annualized (roughly in line with long-run US market averages) is considered a solid baseline. For marketing campaigns, a 200–400% ROI on gross profit is common in well-run digital channels. The right benchmark is always the next-best alternative use of your capital.

What is the difference between ROI and CAGR?+

ROI measures total return over any period without adjusting for time. CAGR (Compound Annual Growth Rate) is the annualized version of ROI — it tells you what consistent yearly growth rate would produce the same total return. Use CAGR whenever you are comparing investments that ran for different lengths of time.

Can ROI be negative?+

Yes. A negative ROI simply means your final value was less than your cost — you lost money. For example, if you invested $10,000 and ended up with $8,500, your ROI is −15%. Negative ROI is useful information: it tells you the magnitude of the loss relative to what was put in.

Why does using revenue instead of profit overstate marketing ROI?+

Revenue includes the cost of the product or service you sold. If your gross margin is 40%, then $10,000 in revenue only represents $4,000 in gross profit. Using revenue as the numerator makes the ROI look 2.5x larger than it actually is, which can lead to badly misallocated ad budgets.

How do I handle taxes when calculating ROI?+

For personal investments, using after-tax returns gives you the most accurate picture of what you actually keep. For business decisions, pre-tax ROI is often used for comparing projects internally (since the tax treatment may be the same for all options), but any final go/no-go analysis on a major investment should factor in the effective tax rate on the gain.