Return on Investment (ROI) Formula

ROI = \frac{\text{Gain from Investment} - \text{Cost of Investment}}{\text{Cost of Investment}} \times 100%

where:
Gain from Investment is the amount of money gained from the investment
Cost of Investment is the initial cost of the investment

Python Code

return_on_investment.py

def return_on_investment(gain, cost):
    roi = (gain - cost) / cost * 100
    return roi


gain = 2400
cost = 2000

roi = return_on_investment(gain, cost)

print("Return on investment: {:.2f}%".format(roi))

# Output: Return on investment: 20.00%