Definition
Cost per lead (CPL) is how much a marketing activity costs for each lead it generates. A lead is someone who showed interest and shared contact details, for example by booking a demo or downloading a guide.
Formula
CPL = spend on the activity ÷ leads generated by it.
Example
A campaign that cost $3,000 and generated 120 leads has a CPL of $25.
Beyond CPL
Cheap leads that never buy are expensive. Follow leads through to customers and compare cost per customer and the revenue those customers bring. For product-led businesses, product-qualified leads are often a better unit than form fills.