How do I measure ROI from my marketing campaigns using analytics?

Measure marketing ROI by tracking both costs and revenue from campaigns. Set up conversion tracking to attribute revenue to campaigns. Calculate ROI as (Revenue - Cost) / Cost × 100. Track costs accurately including ad spend, tool costs, and time. Use attribution models appropriate for your sales cycle. Consider customer lifetime value, not just first purchase. Account for assisted conversions where campaigns help but don't directly convert. Compare ROI across channels to allocate budget effectively. Good analytics setup enables accurate ROI measurement. Many consultants help set up ROI tracking and interpret results. Understanding ROI helps optimize marketing spend and focus on highest-performing channels.