Return on investment (ROI) is the number everyone reaches for to judge whether something was worth the money — a stock, a property, a business, even a marketing campaign. But a single ROI figure can mislead you if you ignore time and costs. This guide shows how to calculate ROI properly, why the annualized version matters, and what counts as a good return. For instant numbers, use our free ROI Calculator.

The ROI Formula

ROI measures your gain or loss as a percentage of what you put in:

ROI (%) = (Final Value − Amount Invested) ÷ Amount Invested × 100

Invest $10,000, end up with $15,000, and your ROI is (15,000 − 10,000) ÷ 10,000 × 100 = 50%, with a $5,000 net profit. End up with $8,000 instead and your ROI is −20% — a loss. The formula works for any investment, in any currency.

Why You Must Annualize: ROI vs CAGR

Raw ROI hides one crucial thing — time. A 50% return is brilliant in one year and disappointing over ten. To compare fairly, convert it to an annual rate using the Compound Annual Growth Rate (CAGR):

CAGR = (Final Value ÷ Amount Invested)^(1 ÷ years) − 1

A 50% total return over 5 years is only about 8.4% per year; over 2 years it’s about 22.5% per year. Same headline ROI, completely different quality — which is why you should always check the annualized figure.

Worked Examples

• Stocks: bought for $5,000, sold for $7,500 after 2 years → 50% ROI, ≈22.5% annualized.
• Slow grower: $5,000 to $7,500 over 10 years → still 50% ROI, but only ≈4.1% annualized.
• Loss: $10,000 down to $8,000 → −20% ROI.

What Is a Good ROI?

There’s no universal “good” — it depends on the asset and the risk. Common benchmarks people cite: the stock market has historically averaged roughly 7–10% per year, real estate is often targeted at 8–12%, and higher-risk ventures may need 15–25%+ to be worth it. The real test is comparing your annualized ROI to a relevant alternative — beating a 4.5% risk-free savings rate by a hair isn’t worth taking on big risk.

The Mistakes That Wreck ROI Calculations

• Ignoring costs: fees, taxes, repairs, and maintenance can turn a 30% headline ROI into 12–18% real ROI. Always include them.
• Ignoring time: never compare raw ROI across different durations — annualize first.
• Ignoring risk: two investments with the same ROI aren’t equal if one is far riskier.
• Ignoring inflation: ROI is a nominal figure; real (inflation-adjusted) returns are lower.

ROI vs Compound Interest

They face opposite directions. ROI looks backward — what return did I actually get? Compound interest looks forward — how much will this grow at a given rate? If you want to project future growth rather than measure past performance, use our Compound Interest Calculator; to plan long-term, try the Retirement Calculator.