Enter your average revenue per customer, gross margin, monthly churn, and acquisition cost. This works out lifetime value and the LTV:CAC ratio — the number that actually tells you whether your acquisition spend makes sense.
Simple LTV model: revenue x margin x average customer lifespan (1 / churn rate). It assumes flat revenue and churn over a customer's life, which real accounts rarely do exactly — treat this as a working estimate, not a forecast. The 3:1 LTV:CAC threshold is a commonly cited SaaS benchmark (David Skok's SaaS metrics work), not a universal rule — a very early or capital-constrained business may need a higher ratio to be safe; a well-funded growth-stage one may run comfortably lower.