The primary PPC KPIs for ROI measurement are: Cost Per Acquisition (CPA) or Cost Per Lead (CPL) - total spend divided by conversions; Return on Ad Spend (ROAS) - revenue divided by spend; Conversion Rate - percentage of clicks completing the target action; Click-Through Rate (CTR) - a Quality Score proxy (benchmark 3–7% for Indian Search campaigns); and Cost Per Click (CPC) - monitors bid competitiveness. For Indian campaigns, segment all KPIs by city and device type to find specific optimisation opportunities. PPC performance also benefits from a well-maintained and fast-loading website - Google awards higher Quality Scores to ads pointing to pages with strong user experience metrics.