[terms] ROI and ROAS

ROI = return on investment = net income / investment = net profit / investment = (total revenue - total cost) / total cost = (gain from investment - cost of investment) / cost of investment = (revenue - COGS) / COGS
<source: various>

ROAS = return on ad spend = (PPC revenue - PPC cost) / PPC cost
<source: https://www.poweredbysearch.com/blog/ppc-advertising-roi-calculator/>