Successful digital marketing ROI measurement considers reach, engagement, and conversion metrics across channels. It also takes industry differences into account. Firms that quantify variables like costs, traffic, conversion rates, and customer lifetime value can make more profitable investment decisions. The study will analyze measurement practices through a survey of global digital marketing managers in different industries. Insights on best practices from platform features and case studies will also be considered to develop a benchmark for cross-industry comparison. Results may show variability in ROI calculation methods between industries but execution quality as the differentiating factor for successful companies.