Use contribution, not sales alone
Multiply attributed incremental revenue by the contribution margin, then subtract creator fees, production, agency, gifting, and other campaign-specific costs not already reflected in that margin. Divide the net amount by the total campaign costs and multiply by 100. With $15,000 in incremental revenue, a 40% contribution margin, and $4,500 in campaign costs, the estimated contribution is $6,000, net contribution is $1,500, and ROI is about 33.33%.
Attribution is the hard part
Codes, tagged links, and landing pages help identify responses, but they miss people who later visit directly and may include customers who would have purchased anyway. Compare with a suitable baseline, note the attribution window, and do not count the same order twice across creators. Track returns and cancellations. A view, like, or comment is not revenue; assess awareness or engagement separately when those are the real objectives.
Include the full cost and disclose the relationship
Creator payments, agency management, production, shipping, samples, discounts, and platform fees can all affect the result. Avoid double counting product costs if they are already included in your contribution margin. The FTC's influencer guidance explains that material brand relationships should be disclosed in endorsements; performance reporting does not replace disclosure. Use this tool as a scenario check, then review invoices and actual order data before making a spending decision.
FTC: disclosures for social media influencers · AMEC: planning meaningful communication outcomes.