ROI

Return on investment (ROI) measures profit relative to what you put in. Amazon's marketing guide gives the formula as revenue minus marketing cost, divided by marketing cost, usually shown as a percentage. If revenue is $9,000 and marketing cost is $2,000, ROI is (9,000 minus 2,000) divided by 2,000, which is 350 percent. The guide also says that for a more accurate result you should consider gross or net profit and include all relevant costs, so the formula is only as honest as the numbers you feed it. ROI is flexible, which is its strength and its weakness. You can compute it for one campaign, one channel, a whole year of marketing, or a purchase of equipment. Always state what is inside the cost and what is inside the return.

The key difference from ROAS is that ROI subtracts cost before dividing. ROAS is revenue over ad spend, so break-even is 1.0 or 100 percent. ROI is net gain over cost, so break-even is zero. A campaign with a ROAS of 2 has a revenue-based ROI of 100 percent, because (2 minus 1) divided by 1 equals 1. People mix the two in a single report, and a reader sees 2 next to 100 percent and does not know which is which. Label units and say which formula you used. Timing matters. A customer acquired this month may keep buying for a year, so first-order ROI can be negative while lifetime ROI is strongly positive. Say which horizon you are using, and when you review, apply the same horizon each time.

What counts as cost is where ROI becomes useful. Amazon's guide says beyond ad spend you should account for staff time and wages, production and creative costs, and overhead, and if you use profit, cost of goods sold, with net profit also subtracting operating expenses, interest, taxes, and other costs. Counting only media spend gives a flattering number. Counting everything gives the true return on the effort. Pick the definition that fits the decision: ad ROI to compare campaigns, full ROI to decide whether a channel is worth running at all. Percentages mislead on small bases. A 300 percent ROI on $100 of spend is $300 of gain, while a 20 percent ROI on $10,000 is $2,000. Show the dollar gain beside the percentage so a high ratio on a tiny budget does not win the argument.

Common mistakes: using revenue instead of profit in the numerator and then calling the result a return. Ignoring the time lag, so an ad that pays back over eight months looks like a loss in month two. Leaving out agency fees and creative costs. Comparing ROI across channels that use different cost definitions. Ignoring that attributed revenue may have occurred without the ad. Also, quoting ROI as a percentage in one place and a multiple in another causes the same confusion as ROAS and ACoS. Do not mix gross and net profit in the same comparison. If one channel's ROI uses gross profit and another's uses profit after labor, the second will always look worse. Choose one basis and apply it to all.

To use it this week, choose one campaign or channel, list every cost tied to it for the last quarter, and calculate ROI on gross profit rather than revenue. Compare this with the ROAS the platform shows, and note the gap. If ROI is low or negative while ROAS looks fine, find which cost you were not counting. Then set a rule for next quarter: the minimum ROI a channel must earn to keep its budget, with a date to review. Compare ROI with the return you could get by using the money another way, such as paying down debt or buying inventory. A positive ROI that is lower than the alternatives is still a poor use of cash.