ROI Calculator
Calculate return on investment as a percentage.
What you provide
Result
ROI %: 50
The saving is the percentage of the original price; the final price is what remains.
- ROI %
- 50
- Net return
- 500
What this cannot tell you
- Pure arithmetic. It does not account for time — a 50% return over one year and over ten years are very different, and ROI alone does not distinguish them.
Take this with you
How this calculation works
ROI is the net gain divided by the amount invested. Enter what you got back and what you put in.
What the results mean
- ROI %
- Net return as a share of the investment. 50% means you made half your investment back on top of it.
- Time not included
- ROI ignores how long the investment took. Compare two investments only if their time frames match, or use an annualised figure.
Common problems and fixes
- Two investments show the same ROI but are not comparable
- ROI has no time dimension, so 50% over a month and 50% over a decade are identical to the formula and utterly different in reality. Annualise before comparing anything with different durations — otherwise the calculation will consistently flatter slow investments and understate fast ones.
- The figure ignores costs I actually paid
- Put every cost into the investment side: fees, taxes, transaction charges, and the time spent if it displaced paid work. ROI computed on the headline amounts alone overstates the return, sometimes substantially on small investments where fixed fees are a large share of the total.
- A negative ROI is confusing to interpret
- It is a loss expressed as a share of what you put in: -25% means a quarter of the investment is gone. The floor is -100%, which is a total loss. There is no lower bound in leveraged positions, where losses can exceed the amount invested — a case this simple formula does not model.
Frequently asked questions
Is a higher ROI always better?
Not without knowing the time frame and risk. A 50% ROI over one month beats 50% over ten years, and a high ROI on a risky bet is not comparable to a modest one on a safe one. ROI is a useful headline figure but always read it alongside how long it took.
How do I annualise an ROI?
Raise one plus the ROI to the power of one divided by the number of years, then subtract one. A 50% return over three years annualises to about 14.5% a year, not 16.7% — dividing by the number of years overstates it, because it ignores compounding. The difference grows with the time period.
Is ROI the right measure for a marketing campaign?
It is a reasonable headline and it hides the hard part: attribution. Revenue that arrives after a campaign is not necessarily caused by it, and the customers who converted may have bought anyway. Compare against a holdout group where you can, and treat a single ROI figure for marketing spend with more scepticism than one for a purchase.
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