Return on Investment (ROI) is one of the most widely used metrics for evaluating whether an investment, project, or purchase paid off. This calculator finds ROI as a percentage from an initial cost and a final value.
Investors, freelancers, and small business owners use ROI to decide between options quickly — should you buy new equipment, run an ad campaign, or take on a new project? Because the formula only needs two numbers, it works for almost any decision where money goes in and a result comes out, from a $50 online course to a $500,000 property purchase.
The formula
For a $1,000 investment that grows to $1,250: gain = $250, and ROI = 250 ÷ 1,000 × 100 = 25%.
Worked examples
| Initial investment | Final value | ROI |
|---|---|---|
| $5,000 | $6,500 | +30% |
| $2,000 | $1,700 | −15% |
| $10,000 | $10,000 | 0% |
A real-world scenario
Say you spend $3,000 on a paid ad campaign that generates $4,200 in sales over two months. Your gain is $1,200, and your ROI is 40%. On its own, that sounds strong — but if a competing campaign returned only 25% ROI in two weeks, the shorter campaign is actually working harder per dollar and per day. This is exactly why raw ROI needs context: the number alone doesn't tell you if 40% is good, average, or worse than the alternative you didn't run.
What ROI does and doesn't capture
ROI is a simple, easy-to-communicate percentage, but it doesn't account for the time period over which the return occurred. A 25% ROI over one year is very different from a 25% ROI over ten years — for comparing investments with different timeframes, an annualized return figure is more appropriate than raw ROI.
See our business math guide for how ROI compares to invoice totals and sales tax calculations.
Common mistakes
- Comparing ROI across different time periods without annualizing. A higher ROI over a much longer period may actually represent a worse annual return than a lower ROI over a short period.
- Ignoring fees and costs. Transaction costs, fees, and taxes should be included in the initial investment or subtracted from the final value for an accurate ROI.
Frequently asked questions
How do I calculate ROI?
Subtract the initial investment from the final value to get the gain, then divide the gain by the initial investment and multiply by 100.
Can ROI be negative?
Yes. A negative ROI means the final value is lower than the initial investment, representing a loss.
Does ROI account for how long the investment was held?
No. Raw ROI doesn't factor in time — an annualized return calculation is more appropriate when comparing investments held for different lengths of time.
What counts as a "good" ROI?
It depends entirely on the context. A 7% ROI on a low-risk savings account is excellent, while the same 7% on a risky startup investment would likely be considered poor given the risk taken. Always compare ROI against the return on a similarly risky alternative, not against a fixed number.