What is return on investment (ROI)?

ROI: definition and formula

Return on investment measures the profitability of an investment. The common formula is: ROI = (benefit − investment) ÷ investment × 100 percent. An ROI of 50 percent means that an investment covered its costs and additionally returned half of its cost as profit.

The figure is popular because it is simple and comparable: it helps decide which of several measures to implement first. But it is only as good as the assumptions behind it. Anyone who records benefits and costs imprecisely gets a seemingly exact but in reality unreliable number.

Calculation example and payback

A business invests €20,000 in automating its quote creation. It expects €12,000 of benefit per year through saved working time and fewer errors. After three years the benefit is €36,000. The ROI is then (36,000 − 20,000) ÷ 20,000 = 80 percent. This is an example calculation with assumed values.

The payback period is often considered as well: investment divided by annual benefit, here about 1.7 years. It shows when the money invested has flowed back. For multi-year projects, more precise methods such as net present value also account for the fact that money in the future is worth less.

Real-world example: is the new software worth it?

A retailer considers connecting orders and warehouse with a merchandise management system. To evaluate it, he collects concrete figures: hours currently spent on reconciliation and corrections, costs from wrong orders and returns, possible extra revenue from more reliable delivery times. He sets all costs against these items, including ongoing ones.

It turns out that part of the benefit cannot be measured in euros, such as more satisfied employees. The retailer lists it separately but calculates only with cautious, verifiable values. The result is a basis for decision that also holds up when the bank or tax advisor asks questions.

Limits, common mistakes and imple­menta­tion

Typical mistakes are incomplete costs (for example only the purchase price instead of total cost, see TCO), overly optimistic benefit, double-counted effects and too short a time frame. ROI also ignores risk and the time value of money. In marketing, it must not be equated with ROAS, which only measures ad revenue relative to ad cost.

Nano Concepts helps evaluate projects economically before they start: we work out effort and expected benefit with you and suggest stages so the investment shows an effect early. After launch, we check together whether the expected effects actually occur.

• Include all costs: development, operation, training, maintenance
• Estimate benefit conservatively and verifiably
• Show non-measurable effects separately
• Choose a realistic time horizon
• After implementation, measure whether the benefit materializes