Return on Investment — ROI — is the most widely used metric for evaluating whether something was worth the money. It works for stocks, real estate, marketing campaigns, business purchases, and almost any financial decision. The math is simple; the interpretation takes a little more thought.
The ROI Formula
ROI = (Net Profit ÷ Cost of Investment) × 100
Net profit is simply final value minus initial cost. If you invested $5,000 and got back $7,500, your net profit is $2,500 and your ROI is (2,500 ÷ 5,000) × 100 = 50%.
What ROI Doesn't Tell You
ROI has one critical blind spot: it ignores time. A 50% return sounds great — but 50% over 10 years is about 4.1% per year, which barely beats inflation. A 30% return in 6 months is exceptional. Always pair ROI with a time period when comparing investments.
💡 CAGR vs ROI: For multi-year investments, use Compound Annual Growth Rate (CAGR) instead of simple ROI. CAGR accounts for compounding and makes different-length investments comparable. A 50% ROI over 10 years is a 4.1% CAGR. Our Investment Return calculator shows both.
Annualized ROI
To compare apples to apples: Annualized ROI = ((1 + ROI)^(1/years)) − 1. A 50% total ROI over 8 years annualizes to about 5.2%. This makes it easy to compare against other investments measured in annual percentage terms.
ROI in Business Decisions
Businesses use ROI to evaluate marketing spend, equipment purchases, and hiring decisions. If a $10,000 marketing campaign generates $35,000 in new revenue with $15,000 in costs, the net profit is $20,000 and ROI is 200% — a strong result. Most businesses target ROI above their cost of capital (typically 8–15%).
What's a "Good" ROI?
It depends entirely on context, risk, and time horizon. Stock market average: roughly 10% annually (7% after inflation). Real estate: typically 8–12%. High-risk startups: investors want 20–30%+ to compensate for risk. Low-risk bonds: 4–5%. The benchmark for any investment is whether its ROI justifies its risk relative to alternatives.