ROI Calculator

The formula is ROI = (return − investment) ÷ investment × 100. Put in $1,000, get $1,500 back, and you have $500 of gain and a 50% ROI. Notice that the divisor is the investment, not the return. That is why ROI passes 100% without difficulty: doubling your money is 100%, tripling it is 200%, and a tenfold return is 900%. On the downside there is a floor. Losing everything means a return of zero and an ROI of −100%, the worst possible outcome when no borrowed money is involved. An ROI of −30% means $700 came back out of every $1,000 committed.

The single most common error is putting revenue in the return field. Revenue is not what came back to you — it is what passed through the register on its way to suppliers, processors and payroll. A trade show booth that cost $1,000 and produced $4,000 in sales did not return 300%. Those sales carry product cost, fulfillment and payment fees. If the contribution margin is 30%, the real return is 4,000 × 0.30 = $1,200, and the ROI is (1,200 − 1,000) ÷ 1,000 = 20%. The distance from 300% to 20% is the distance between a decision that looks obvious and one that barely clears. The rule: the numerator holds money that actually stayed with you, not money that merely moved. The denominator has to be complete too — budget, tools, travel, materials, and the cost of staff time where it is material.

Two investments with 50% ROI can be wildly different: one took six months, the other took five years. The formula has no term for time, so it reports them identically. To compare across horizons you annualize: annual rate = (1 + ROI)^(1 ÷ years) − 1. That 50% over six months is roughly 125% a year. The same 50% over five years is roughly 8.4% a year. One is fifteen times the pace of the other, and raw ROI showed no difference at all. The companion metric is payback period — how long until the money comes back: investment ÷ return per period. A $12,000 project returning $1,000 a month has a 12-month payback, and reaches 100% cumulative ROI at 24 months. Payback speaks to risk and cash flow; ROI speaks to the size of the eventual gain. Serious decisions want both.

ROI and ROAS are cousins that are constantly confused. ROAS = revenue ÷ ad spend, and it does not net out the cost of what you sold. ROI = profit ÷ investment, and it does. Because of that, a healthy-looking ROAS can sit on top of a loss. At a 20% contribution margin, a 3× ROAS returns 3 × 0.20 = 0.60 of margin per dollar spent — you are losing forty cents on the dollar. Your break-even ROAS is 1 ÷ margin, which at 20% is 5×. Converting between them is straightforward: ROI = (ROAS × margin) − 1. A 5× ROAS at a 30% margin is (5 × 0.30) − 1 = 0.50, or 50% ROI. Anyone reporting campaign performance in ROAS alone is reporting half the picture.

Beyond time, three things sit outside the formula. Risk. Two projects with an expected 40% ROI are not equivalent if one is far likelier to miss. ROI is always computed on a single outcome, realized or projected, and a projection is not a fact. Scale. A 200% ROI on $500 returns $1,000. A 20% ROI on $200,000 returns $40,000. The bigger percentage is not the better deal when you have capital available for the second. Attribution. In marketing especially, some of the result would have happened anyway. Crediting every sale to the campaign inflates the return; comparing periods with and without the spend gives a more honest read on the incremental effect. Over long horizons, inflation matters too: a positive nominal ROI can still be a loss in purchasing power. This calculator is an analysis tool, not investment advice; weigh any financial decision against your own circumstances and, where appropriate, a qualified professional.