Return on Investment (ROI) is a key performance metric used to measure the profitability and effectiveness of an investment. It shows how much return or benefit a business gains compared to the amount of money, time, or resources invested. ROI helps companies understand whether an effort—such as a marketing campaign, product launch, advertisement, or operational upgrade—has delivered valuable results.

ROI is typically calculated using the formula:
ROI = (Net Profit ÷ Investment Cost) × 100

A positive ROI indicates success and profitability, while a negative ROI signals loss or inefficiency. In marketing, ROI is used to evaluate campaign performance by comparing outcomes like leads, sales, traffic, or engagement against the cost invested. By tracking ROI, businesses can make smarter decisions, allocate budgets effectively, optimize strategies, and focus on activities that deliver the highest value and growth.