LTV:CAC ratio (customer lifetime value to customer acquisition cost ratio)

The LTV:CAC ratio divides customer lifetime value by customer acquisition cost: LTV / CAC. A ratio of 3:1 means a customer is expected to generate three dollars of value for every dollar spent acquiring them. It is one of the standard unit economics checks used to judge whether a growth strategy is fundamentally sound.

LTV itself is an estimate, usually built from average revenue per account, gross margin, and expected customer lifespan or churn rate, so the ratio is only as reliable as the assumptions behind it; a short observed history or a changing churn rate can make LTV unstable. The ratio also says nothing about timing: it treats a dollar returned in month two the same as a dollar returned in year three, which is why it is normally read alongside CAC payback period, which measures how fast, not how much.

A commonly cited SaaS benchmark is roughly 3:1 or higher, with a very high ratio, such as 10:1, sometimes read not as excellence but as underinvestment in growth. The common pitfall is using customer acquisition cost figures that exclude real costs like sales salaries or onboarding, or projecting LTV over an optimistic lifespan not supported by actual retention data, both of which inflate the ratio.