Glossary
ROI
Meaning and details
ROI is the arithmetic of justification: subtract cost from gain, divide by cost, express as a percentage. Spend 2,000 on a campaign that returns 3,400 in gross profit and the ROI is 70 percent. The formula is trivial; th...
ROI meaning
Return on investment: the gain or loss from a spend, expressed as a percentage of what it cost.
What is ROI?
ROI is the arithmetic of justification: subtract cost from gain, divide by cost, express as a percentage. Spend 2,000 on a campaign that returns 3,400 in gross profit and the ROI is 70 percent. The formula is trivial; the discipline is in what counts as gain, over what window, and whether the comparison is against doing nothing or against the next-best use of the same money, which is the question ROI exists to answer honestly.
Why it matters to an indie builder: capital and time are both scarce and interchangeable, and ROI is how you stop guessing which allocation earns its keep. It also protects against the two chronic founder pathologies: refusing to spend on anything, which starves growth, and spending on everything that sounds strategic, which starves focus. A rough ROI estimate made before the spend, and an honest one after, converts marketing and tooling from vibes into a portfolio.
A concrete example: a $60/month SEO writing tool subscription. Over a quarter it produces content that brings 4,100 visits and 19 trials, of which 6 convert at $29 monthly with average tenure predicted at 14 months: revenue attributable around $2,400. Tool cost for the period: $180, plus 30 hours of founder time at a self-imposed $50 rate: $1,680 total. ROI: about 43 percent, positive but modest, and the honest conclusion is the tool is fine but the founder hours are the real cost line, so the next experiment is delegating the drafting. That refinement, invisible in the naive calculation, only appears when time is priced in.
Common mistakes: measuring revenue instead of profit (a 3,400 campaign that costs 2,900 in serving and support is a loss wearing a win), cherry-picking attribution windows until the number turns positive, omitting founder time because it feels free, which systematically overrates DIY and underrates tools and delegating, and demanding ROI precision where direction suffices, at small scale, rank-ordering the options beats a spreadsheet to the third decimal. See ltv, cac and kpi for the metrics this feeds.
How is ROI calculated?
ROI is calculated by taking the gain from an investment, subtracting the cost of the investment, and dividing the total by the cost of the investment. Or, ROI = (Net Profit / Cost of Investment) x 100.