ROI Calculator

Measuring a return

Return on investment shows your gain as a percentage of what you put in: profit divided by the amount invested. It is the simplest way to answer "was this worth it?" But a raw ROI hides one crucial detail, time. A 50% gain in one year and a 50% gain over ten years are worlds apart, so this calculator also gives the annualised return, the equivalent steady yearly rate, which lets you compare investments fairly no matter how long each ran.

That annualised figure is the one that matters most when you are choosing between options. Headline totals flatter long, slow investments and understate quick ones. Converting everything to a per-year rate strips that distortion away.

Two examples

Turn 1,000 into 1,500 and you have a 50% ROI and a 500 profit. If it took three years to get there, the annualised return is about 14.5% a year, which is genuinely strong.

Now imagine another investment that also returned 50%, but over ten years. Same headline ROI, yet the annualised return is only about 4.1% a year. On the total they look identical; on the annual rate the first is more than three times better. That is exactly why annualising matters.

Using it well

• Compare investments on the annualised return, not the headline total.
• Weigh the return against the risk taken. A high ROI on a risky bet is not the same as a steady one.
• Line the annual rate up against alternatives like savings rates or index funds for honest context.

What it does not include

This compares a single amount in against a single amount out. It does not account for extra contributions along the way, dividends reinvested, fees or tax, all of which affect your true return. For a plan with regular monthly contributions, use the investment calculator instead. Treat ROI as a clean scorecard for one lump sum, not a full picture of a complex portfolio.