Where ROAS is based on revenue, ROI is based on profit after costs. The same campaign can have high ROAS and low ROI.
When looking at marketing ROI, include not just ad spend but content production, agency fees and labor in the investment cost to get closer to reality.
Formula
ROI (%) = (profit gained from the investment − investment cost) ÷ investment cost × 100
Sample If you spent KRW 3 million on marketing and profit after costs rose by KRW 4.5 million, ROI is (450 − 300) ÷ 300 × 100 = 50%.