The Complete Guide to Return on Investment (ROI)
By Arshi Khan, Founder of Just4Marketing · Last reviewed October 2026
Return on Investment (ROI) is the most common way to measure how efficiently money put into something turned into profit. This guide covers the formula, what counts as a good ROI across different investment types, and the mistakes that most often distort the number.
What is ROI and why does it matter?
Return on Investment measures how much profit an investment generated relative to what it cost, expressed as a percentage: ROI = (Amount returned − Amount invested) ÷ Amount invested × 100. Because it strips everything down to a single percentage, ROI lets you compare completely different kinds of investments — stocks, real estate, a small business, an ad campaign — on the same scale.
The tradeoff for that simplicity is that plain ROI ignores time. A 20% ROI earned in six months is a very different result from a 20% ROI earned over five years, which is why the annualized version of the formula matters whenever you're comparing investments of different durations.
What's considered a good ROI?
There's no single "good" number — it depends on the asset class and the risk involved. These are typical annualized ranges seen across common investment types:
| Investment type | Typical annual ROI |
|---|---|
| Savings accounts / CDs | 1% – 5% |
| Government / corporate bonds | 3% – 6% |
| S&P 500 (long-term average) | 7% – 10% |
| Residential real estate | 8% – 12% |
| Small business | 15% – 30%+ (highly variable) |
| Marketing campaigns (as ROAS) | 200% – 400%+ (3:1 – 5:1) |
Key factors that affect your ROI
Time horizon changes the picture
Always annualize before comparing two investments held for different lengths of time — a higher total ROI over a longer period can still be a worse annual rate.
ROI doesn't measure risk
Two investments with identical ROI can carry very different risk of loss. A higher ROI should usually come with higher, not equal, risk.
Be consistent about what counts as 'invested'
Decide up front whether fees, taxes, and closing costs are included in your invested amount, and apply that same rule every time you calculate ROI so comparisons stay fair.
Nominal ROI ignores inflation
A positive ROI can still represent a real loss in purchasing power if inflation over the same period was higher than your return.
Frequently asked questions
What counts as a good ROI?
It depends heavily on the asset class and time period. A savings account returning 4% a year is solid for its risk level, while a small business or marketing campaign might target 20% or more because the risk is much higher. Always compare ROI against similar-risk alternatives, not a single universal benchmark.
How is ROI different from annualized ROI?
ROI is the total return over the entire time you held the investment, regardless of how long that was. Annualized ROI converts that into an equivalent yearly rate, using (Final ÷ Initial)^(1/years) − 1, which is the only fair way to compare investments held for different lengths of time.
Does ROI account for inflation?
No, the standard ROI formula uses nominal dollars. A 5% ROI during a year of 6% inflation represents a real loss in purchasing power. For long holding periods, it's worth comparing your ROI against the inflation rate over the same period.
Can ROI be negative?
Yes. If the amount returned is less than the amount invested, net profit is negative and ROI comes out below 0%, meaning the investment lost money overall.