What is LTV:CAC ratio? Definition, Formula & Benchmarks

What is ltv:cac ratio?

The LTV:CAC ratio compares the lifetime gross profit from a customer to the cost of acquiring them. You divide customer lifetime value by customer acquisition cost. A ratio of 3:1 is the widely cited minimum for a viable model, under 1:1 means you lose money on every customer, while very high ratios can signal underinvestment in growth.

Formula

LTV:CAC = Customer Lifetime Value ÷ Customer Acquisition Cost

Customer Lifetime ValueGross profit expected from a customer over their full relationship
Customer Acquisition CostFully loaded cost to acquire one new customer

Worked example

A startup with an LTV of $18,000 and a CAC of $4,500 has an LTV:CAC ratio of 4:1, it earns four dollars of lifetime gross profit for every dollar spent acquiring a customer, comfortably above the 3:1 floor.

Benchmarks by stage

3:1 is the minimum viable threshold and top companies run 4:1–6:1; the 2024 median for private B2B SaaS was 3.6:1.

< 1x · Losing money

1–3x · Improving

3–5x · Healthy

> 5x · Underinvesting

Source: David Skok (SaaS Metrics 2.0) & Benchmarkit 2025 SaaS Performance Metrics (2025)

Why it matters for fast-growing companies

LTV:CAC is the single number investors use to judge whether growth is profitable and scalable. A strong ratio justifies spending more to grow; a weak one signals you're buying revenue that never pays back.

Frequently asked questions

What is a good LTV:CAC ratio?+

3:1 is the widely cited minimum for a viable model, and top performers run 4:1 to 6:1, per David Skok and 2025 SaaS benchmark data. Below 3:1 suggests weak unit economics; far above 5:1 often means you're underinvesting in growth and leaving expansion on the table.

Can an LTV:CAC ratio be too high?+

Yes. A ratio above 5:1 usually signals you're underspending on acquisition and could grow faster by investing more. Investors read very high ratios as leaving market share on the table, not as a badge of efficiency, especially for a venture-backed startup expected to scale.

How often should we recalculate LTV:CAC?+

Review it quarterly at minimum, and monthly if you're actively scaling spend. CAC and churn shift as you enter new channels or segments, so a ratio that looked healthy last year can erode quietly. Cohort-level tracking catches problems earlier than a blended number.

LTV:CAC ratio