Cost per Lead (CPL)
The campaign cost required to acquire one new lead.
Cost per lead measures spending per acquired contact that meets your lead definition. In SaaS, a lead could be a demo request or a relevant person who signs up for an educational resource. The metric is useful when a buyer needs nurturing or sales help before purchase.
Example: An operations SaaS spends $750 promoting a webinar and receives 50 new eligible registrations. CPL is $15. Only ten registrants fit its target account profile, however, so the cost per fit-qualified lead is $75. Separating the figures reveals whether the campaign is producing volume or useful demand.
Watch out: A lead is not a customer, and a low CPL can conceal a weak buying audience. Deduplicate repeated submissions, remove spam, and make your qualification criteria explicit. Do not count existing contacts as new leads unless the report specifically measures reengagement. Evaluate progression to qualified opportunities and customers before scaling a campaign purely because registrations are cheap.
Further reading: Ahrefs: lead generation.
Related: MQL, lead qualification.