LTV:CAC ratio: what a good ratio looks like and how to calculate it honestly

What is a good LTV:CAC ratio?

Above 3. In SaaS Metrics 2.0, David Skok, a partner at Matrix Partners, writes that the best SaaS businesses run above 3 and that top performers reach 7 or 8. He also notes that plenty of healthy companies start below that and improve their way there. Read the ratio in bands rather than as a pass mark:

How do you calculate customer acquisition cost?

Take total sales and marketing spend for a period and divide it by the new customers won in the same period. Andreessen Horowitz asks for the full cost, stated per customer: ads, the salaries and commission of the people who sell and market, tools, agencies, content. Leaving people out is the most common way to produce a CAC that looks great and is not.

Then split it. Blended CAC spreads all spend over all new customers, including those who arrived through word of mouth or search. Paid CAC divides paid-channel spend by the customers those channels brought in. a16z points out that blended CAC tells you nothing about whether paid campaigns are profitable, and that investors weight paid CAC more heavily.

How do you calculate LTV?

Monthly margin per customer multiplied by average customer lifetime, where lifetime is 1 divided by monthly churn. The argument is over which margin to use. Stripe's Billing analytics shows a quick revenue-based estimate, average revenue per user divided by churn. Skok's traditional formula uses gross profit. a16z goes further and asks for contribution margin, because a revenue-based LTV suggests you can spend more on acquisition than you really can.

For budget decisions, use gross margin at the very least. If your customers expand a lot over time, Skok's discounted cash flow version of LTV handles expansion better than the simple formula, which can run to infinity once churn turns negative.

Now stress-test it. If true churn is 5% rather than 2.5%, LTV halves to $1,500 and the paid ratio drops to 2.5: from comfortable to marginal by changing one input. That is why the churn estimate deserves more care than any other number here; our guide to SaaS churn rate covers how to get it right.

Why does CAC payback matter as much as the ratio?

Because it relies on the months you can see rather than the years you cannot. CAC payback is CAC ÷ monthly gross margin per customer: in the example, $400 ÷ $75 ≈ 5.3 months blended and $600 ÷ $75 = 8 months paid. Skok's guidance is to recover CAC within 12 months, with the best SaaS companies doing it in 5–7; with easy access to plenty of capital, he says 18 months or more can be acceptable.

The acceptable payback also depends on who you sell to. Bessemer Venture Partners' Scaling to $100 Million measures payback against gross-margin-adjusted ARR and sets targets of under 12 months for SMB, under 18 for mid-market and under 24 for enterprise, where customers stay longer. On the ratio itself Bessemer lands where Skok does: invest in acquisition when lifetime value is at least 3x CAC.

Payback also tells you how much cash growth will consume. A ratio of 5 with a 30-month payback can still starve a seed-stage company, because the money comes back long after it went out.

Bill Gurley's warning about the LTV formula is worth reading before any board meeting. His points: the inputs move together (raise prices or push marketing and churn may rise), bought customers tend to churn more than organic ones, and paid channels get dearer as you spend more. In his words, LTV is a tool, not a strategy.

When is the LTV:CAC ratio meaningless?

Whenever acquisition is not yet repeatable. Skok himself cautions that CAC and LTV formulas only give meaningful results when sales and marketing processes are predictable and scalable. Ten customers from the founders' network give you a CAC near zero and an LTV that is pure projection, and dividing one by the other proves nothing.

Before that point the question is whether anyone truly needs the product, which is what the product-market fit survey measures. Once the answer is yes and a channel works twice in a row, the ratio earns its place among the other SaaS metrics that matter. Improving it then comes down to four levers: lower CAC, higher revenue per customer (see SaaS pricing models), better margin and, most powerful of all, lower churn.