What Is Return on Investment?

ROI is one of the most intuitive and widely used financial metrics because it directly answers: "What return did we get for our money?" Its simplicity makes it accessible across the organisation, from the board room to department heads seeking budget approval.

The basic formula is: ROI = (Net Benefit / Investment Cost) x 100, where Net Benefit = Total Returns - Investment Cost. An ROI of 150% means the investment generated 1.5 times its cost in net returns.

Despite its popularity, ROI has important limitations. It does not account for the time value of money — a 50% ROI over one year is vastly different from 50% over ten years. It does not consider risk — a guaranteed 10% ROI may be preferable to a risky 30% ROI. And it can be manipulated by changing the scope of what counts as costs versus benefits.

For more sophisticated investment analysis, FP&A teams typically supplement ROI with time-adjusted metrics like Net Present Value (NPV) and Internal Rate of Return (IRR). These address the time value limitation by discounting future cash flows.

Common ROI applications in FP&A include technology investment evaluation (will this new system save enough to justify the cost?), marketing spend analysis (what revenue does each campaign generate?), hiring decisions (what is the ROI of adding a sales rep?), and M&A assessment (what return will this acquisition generate?).

For UK businesses, ROI calculations should account for corporation tax implications, capital allowance benefits, and any applicable government grants or incentives that reduce the effective investment cost.