By Jessica Martinez"What's the ROI?" is one of the more common questions in a business, and one of the more commonly answered badly, usually because the cost side of the equation quietly leaves something out. Get that part right and the formula itself takes about ten seconds.
ROI = ((Return - Cost) / Cost) x 100. Return is what came back. Cost is what went in. A $5,000 investment that generates $7,500: ROI = ($2,500 / $5,000) x 100 = 50%.
Simple ROI ignores time. A 50% ROI over 10 years is not the same proposition as a 50% ROI in 6 months, though both report the same number. Annualized ROI corrects for this: Annualized ROI = ((1 + ROI)^(1/years) - 1) x 100. A 50% ROI over 2 years annualizes to about 22.5% per year, which is a meaningfully different claim.
ROI is a ratio, not a dollar amount. A 200% ROI on a $1,000 investment is $2,000 in profit. A 20% ROI on $100,000 is $20,000 in profit. The higher percentage produced the smaller payoff. ROI also ignores risk, liquidity, and what else you could have done with the money. Use it as one input alongside absolute returns and your actual business constraints.
For business investments, an annual ROI above 10 to 15% is generally considered reasonable, since it exceeds what could be earned by putting the same capital into an index fund. Marketing ROI varies sharply by channel: email marketing is often cited at 3,600% ($36 return per $1 spent), while paid search typically targets 200 to 400% depending on product margins and customer lifetime value. Those figures assume the cost accounting is honest.
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ROI is profit divided by investment cost, expressed as a percentage. A 100% ROI means you doubled what you put in. A negative ROI means the investment cost more than it returned. The formula works on any investment, but requires careful accounting of all costs, not just the obvious ones.
ROI = ((Return - Investment Cost) / Investment Cost) x 100. Spend $2,000 on advertising, generate $6,000 in revenue with $3,000 in product cost: net gain is $1,000. ROI = ($1,000 / $2,000) x 100 = 50%. Note that only the ad spend is in the denominator here, not the product cost, which is the most common source of inflated marketing ROI claims.
It depends on the investment type and the timeframe. For business capital investments, 10 to 15% annually is a reasonable floor, since it needs to beat what passive index investing could return. Marketing ROI targets are typically much higher because the capital is deployed and returned within months, not years. A 200% annual ROI on a piece of equipment and a 200% ROI on a three-month ad campaign are not equivalent propositions.
Profit margin is profit as a percentage of revenue, showing how much of each sale survives after costs. ROI is profit as a percentage of the investment cost, showing what you earned relative to what you committed. Margin evaluates ongoing operations. ROI evaluates a specific decision or investment. Both are worth tracking; they are rarely interchangeable.
Jessica Martinez covers the math behind everyday business decisions: what to charge, what to expect back, and what a number actually means once the optimism is stripped out. A former credit analyst, she still reads every figure the way she'd read a loan file: twice, and slowly.
