An investment ROI (Return on Investment) calculator tells you how profitable an investment was relative to what it cost you. It is one of the most widely used metrics in personal finance and business because it works for any type of investment — stocks, real estate, a business, or even a course. Investors, entrepreneurs, and analysts use it to compare opportunities and evaluate past performance with a single, easy-to-understand percentage.
How to Use This Calculator
- Enter the initial investment cost — the total amount you put in.
- Input the final value or return — what the investment is worth now, or what you received from it.
- Optionally enter the holding period to see annualized ROI.
- Review the net profit, ROI percentage, and annualized return.
What This Calculator Measures
The ROI calculator measures how efficiently an investment converts cost into profit.
- Net profit — The gain after subtracting the original cost from the final value.
- ROI percentage — Net profit expressed as a percentage of the original cost.
- Annualized ROI — The equivalent yearly return, useful for comparing investments held over different time periods.
- Cost basis — The total amount invested, including any fees or additional contributions.
Formula or Logic
The ROI formula is:
ROI = (Net Profit / Cost of Investment) × 100
Where Net Profit = Final Value − Initial Cost. For example, if you invested $1,000 and received $1,350 back, your net profit is $350 and your ROI is 35%. To compare investments held for different durations, the annualized ROI uses the compound annual growth rate (CAGR) formula, which accounts for the holding period.
Example Calculations
Example 1: You buy stock for $2,000 and sell it for $2,800 after two years. Net profit: $800. ROI: 40%. Annualized ROI: approximately 18.3%.
Example 2: You invest $5,000 in a rental property improvement and the property value rises by $9,000. Net profit: $4,000. ROI: 80%.
Understanding Your Results
A positive ROI means the investment made money; a negative ROI means it lost money. Always compare ROI to a benchmark — like a market index return — to judge whether an investment was truly worth it. Annualized ROI is more useful than simple ROI when comparing investments held for different lengths of time, because it puts them on a per-year basis.
Common Mistakes to Avoid
- Excluding fees, commissions, and taxes from the cost calculation
- Comparing simple ROI across investments with very different time horizons without annualizing
- Ignoring opportunity cost — what you could have earned investing elsewhere
- Treating projected future ROI as if it were guaranteed