Visitors arrive; only some take the desired action. Conversion rate is the percentage who do. For an e-commerce site the action may be a purchase; for a lead-generation page it may be a form submission; for a content site it may be a newsletter signup. The rate is calculated by dividing conversions by total visitors or sessions and expressing the result as a percentage.

Conversion rate is one of the most closely watched metrics in digital marketing because it directly links traffic to results. Small improvements can have large effects on revenue when traffic volume is high. Optimization work—better page design, clearer offers, reduced friction—aims to raise the rate without necessarily increasing the cost of acquiring visitors.

Benchmarks differ widely by industry and by the difficulty of the conversion. A 1 percent rate may be excellent for a high-priced product and poor for a free trial. Tracking the rate over time and by traffic source helps marketers allocate resources and diagnose problems. Ultimately conversion rate measures how effectively a site or campaign turns attention into action.