What is the LTV:CAC ratio

LTV:CAC ratio compares the lifetime value of a customer (LTV) to the cost of acquiring that customer (CAC). A commonly cited benchmark is 3:1, meaning a customer should be worth roughly three times what it cost to acquire them, though the right target varies by business model and sales cycle.

The formula

LTV:CAC = customer lifetime value divided by customer acquisition cost.

Customer lifetime value is typically estimated as average revenue per account, multiplied by gross margin, divided by churn rate (or multiplied by average customer lifespan in months or years). Customer acquisition cost is total sales and marketing spend over a period, divided by the number of new customers acquired in that period. Both sides of the ratio need to use the same time window and the same customer segment, or the comparison stops meaning anything.

How to read the result

A ratio below 1:1 means you're losing money on every customer before you even factor in delivery cost. Around 1:1 to 2:1, the business is straining: growth is expensive relative to what it returns. A ratio of 3:1 or higher is often treated as healthy, though a very high ratio (10:1, for instance) can also signal underinvestment in acquisition, not just efficiency.

The ratio is a snapshot, not a verdict. A B2B company with long contracts and high retention can sustain a lower ratio for longer than a company selling a low-commitment monthly plan. Context matters more than the number in isolation.

Getting started without a full LTV model

A precise LTV calculation needs churn data, margin data, and often cohort-level revenue history. Most teams don't have all of that clean and ready on day one, and that's fine. Start with a simplified LTV, average revenue per customer over a fixed period (say, 12 months), even before churn and margin are fully accounted for. Refine the model once the basic ratio is in place and being tracked consistently. The point is to start tracking a directionally useful number, not to wait for a perfect one.

CAC and retention data often live in separate systems, marketing spend in one place, product usage and churn signals in another. Funnelsight's single source of truth approach keeps usage, retention, and revenue data in one shared view, which is what LTV:CAC tracking depends on once you move past a one-time spreadsheet calculation.

Why it matters for PLG and hybrid motions

In a self-serve or hybrid PLG motion, CAC is easy to undercount if free trial and marketing costs aren't fully attributed, and LTV is easy to overstate if expansion revenue isn't tracked separately from new business. Teams running a self-serve motion alongside a sales-assisted one should calculate the ratio per motion, not blended, since the two usually have very different acquisition costs and retention profiles.