Cost Per Lead (CPL) is a marketing metric that measures the amount of money spent to acquire a single lead—typically defined as a potential customer who has shared their contact information. In B2B SaaS, CPL is the primary KPI for the demand generation team. It is calculated by dividing the total marketing spend by the number of qualified leads generated. CPL allows businesses to put a price tag on their 'Sales Pipeline' and determine which channels (e.g., webinars, whitepapers, or paid search) are the most cost-effective for finding prospects. However, CPL should never be viewed in isolation; a 'cheap' lead that never converts to a sale is worthless compared to an 'expensive' lead that has high intent. Therefore, professional teams often track 'Cost Per Marketing Qualified Lead' (CP-MQL) and 'Cost Per Sales Qualified Lead' (CP-SQL) to ensure that the marketing budget is being spent on high-quality prospects who are actually likely to close.