ROI stands for Return on investment. It is found by dividing the net profit gained by the total assets. It is expressed in percentage. The given ROI formula is subtracting the net profit (earning) with the invested amount and dividing the resultant value with the total invested amount again. If the resultant value is positive, it means there is a gain for investment. Below given is the ROI Formula to calculate the return on investment based on the earnings and investment.