What ratio of CAC to LTV is healthy?

The canonical 1:3 benchmark

The CAC:LTV ratio (Customer Acquisition Cost to Lifetime Value) measures whether each customer is profitable. The 1:3 minimum is the industry-canonical benchmark, originating from David Skok at Matrix Partners ("SaaS Metrics 2.0") and Bessemer Venture Partners.

``` Ratio = LTV / CAC

LTV = ARPU × Avg Customer Lifetime × Gross Margin % CAC = (Sales + Marketing spend) / (New customers acquired) ```

A customer with $1,500 LTV and $500 CAC has a 1:3 ratio. Healthy. A customer with $1,500 LTV and $1,200 CAC has a 1:1.25 ratio. Marginal.

Full benchmark table

Why 1:3 specifically (not 1:2 or 1:5)

The 1:3 threshold incorporates three realities:

1. CAC understatement risk — most companies underreport CAC by 30-50% (excluding salaries, mixing time windows). Real CAC is often 1.3-1.5× reported. 1:2 reported = 1:1.3-1.5 actual = marginal.

1. LTV overstatement risk — most companies overestimate LTV by 1.2-3× (using revenue not gross profit, assuming steady-state churn that hasn't materialized). Real LTV is often 0.7-0.85× reported.

1. Combined effect — Reported 1:3 ratio + both biases = real 1:1.5-2 ratio = marginal. So 1:3 reported is the threshold where, even with typical reporting bias, the actual unit economics are still profitable.

If you can demonstrably show CAC is fully-loaded AND LTV uses gross-profit-not-revenue, then 1:2 may be acceptable. Most can't, so 1:3 is the rule.

Why ratios above 1:5 are suspicious

A 1:5 ratio means each customer pays you 5× what they cost to acquire. Sounds great, but in healthy growth companies this is rare for one of three reasons:

1. Under-investing in growth — You COULD acquire more customers and grow faster, but you're being too conservative on spend.

1. Inflated LTV — Using revenue-LTV instead of gross-profit-LTV; assuming optimistic churn rates that haven't held in real cohorts; including outliers.

1. Understated CAC — Excluding salaries; not counting failed trial-to-paid acquisition costs; mixing time windows.

Investigate which before celebrating.

The CAC Payback Period (companion metric)

CAC:LTV ratio alone misses cash-flow timing. The companion metric:

``` CAC Payback = CAC / (Monthly ARPU × Gross Margin %)

= How many months until you recover the cost of acquiring this customer ```

Healthy thresholds: - <12 months: Excellent - 12-18 months: Healthy - 18-24 months: Acceptable for enterprise - >24 months: Usually unsustainable

A 1:5 ratio with 36-month payback is worse than 1:3 with 6-month payback. Cash flow matters even when unit economics look great.

Calibration by company stage

The 1:3 canonical is for "the median healthy SaaS." Early-stage often runs hot (high CAC, low LTV until product matures). That's acceptable temporarily; not acceptable indefinitely.

Common ratio-calculation mistakes

• Reporting "marketing CAC" not "fully-loaded CAC" → ratio looks 1.5-2× better than reality
• Using revenue-LTV not gross-profit-LTV → ratio looks 1.2-3× better than reality
• Cherry-picking the best cohort → ratio reflects best-case not average
• Averaging across segments with very different economics → average hides actionable variance
• Not segmenting by channel → paid social may have 1:1 ratio while organic search has 1:8

Cross-reference: see /pages/what-is-the-difference-between/cac-and-ltv (the underlying definition) + /pages/what-is/customer-acquisition-cost + /pages/what-is/lifetime-value.