ROI Calculator

Return on investment expresses gain relative to cost. The simple version answers "how much did this make me?"; the annualized version answers "at what rate?" — and they can lead to opposite rankings.

What ROI measures

Return on investment is the ratio of net gain to the amount put in. It is the most cited and most misused metric in business analysis because it discards two pieces of information that often matter more than the ratio itself: how long the money was tied up, and what else it could have done in the meantime.

Simple ROI = (Final value − Initial investment) / Initial investment

Annualized ROI = (1 + Simple ROI)^1/n − 1, where n is years held

When to use simple ROI

Simple ROI is appropriate when you are comparing investments of similar duration, or when you only need a back-of-the-envelope sense of magnitude. It is also the right metric for one-shot operating decisions where there is no realistic alternative deployment of the capital — say, deciding whether a $4,000 conference produced more than $4,000 of attributable revenue.

When to use annualized ROI

For anything held longer than a year, or when comparing investments of different durations, annualize. A 60% return over five years sounds impressive until you see it as 9.86% annualized — below the long-run S&P 500 average. The annualization formula above is identical to CAGR; the two terms are interchangeable when there are only two cash flows (initial and final).

Worked example

You bought equipment for $50,000, used it for three years, and sold it for $20,000 after generating $45,000 in net cash flows over that period. Total proceeds: $65,000. Net gain: $15,000. Simple ROI: 30%. Annualized ROI: 9.14%. The same nominal gain over one year would be a 30% annualized return — far better — which is why the holding period is essential context.

What ROI doesn't account for

Risk. A guaranteed 8% beats a 50/50 shot at 20% for most decisions; ROI alone says nothing about variance.
Time value of money. A dollar earned in year five is worth less than a dollar earned in year one. For multi-year cash flow streams, prefer NPV or IRR.
Opportunity cost. ROI is silent on what the capital could have earned elsewhere. The right benchmark is your hurdle rate, not zero.
Ongoing capital and operating costs. Many "ROI" calculations omit installation, training, or maintenance. Use a fully-loaded cost figure or you'll consistently overstate returns.

Common ways ROI gets gamed

Sales decks frequently quote ROI without specifying the period, or include only the easiest-to-attribute revenue while excluding effort hours, opportunity cost, or downstream churn. When evaluating a vendor's ROI claim, insist on three things: the time window, the full cost base, and the counterfactual.