LTV:CAC Ratio

The LTV:CAC ratio compares what a customer is worth over their lifetime to what you paid to acquire them. It is the most quoted unit-economics number in SaaS because it collapses the whole business model into one figure: for every dollar spent on acquisition, how many dollars of customer value come back?

A ratio above 1:1 means customers are worth more than they cost — necessary, but nowhere near sufficient, because LTV arrives over years while CAC is paid up front. That timing gap is why the accepted healthy benchmark sits around 3:1, not 1:1.

Divide customer lifetime value by customer acquisition cost, computed over the same customer segment. A $6,000 LTV — $200 a month at 75% gross margin over a 40-month lifespan — against a $2,000 CAC gives a ratio of 3:1.

Use gross-margin-adjusted LTV, not raw revenue, or the ratio flatters you by the size of your cost of service. And keep the segments honest: blending an efficient self-serve motion with an expensive enterprise one produces a ratio that describes neither.

The classic reading: around 3:1 is healthy, below 1:1 is losing money on every customer, and 5:1 or higher may mean you are under-investing in growth — money left on the table while competitors buy the customers you didn't.

Treat the benchmark as a range, not a law. Early-stage companies routinely run below 3:1 while channels mature; efficient PLG businesses run far above it by design. What matters most is the direction — a ratio that improves as you scale says the engine compounds, one that decays says you are buying progressively worse customers.

The ratio inherits every judgement call in both of its inputs — fix these first:

• Projected or realized LTV? Projected assumes today's churn holds for years; realized only counts collected revenue.
• Blended or paid CAC in the denominator — the ratio can double depending on the answer.
• One ratio or one per acquisition motion? Segment-level ratios are the ones you can act on.