Formula
CAC = acquisition spend divided by new customers. Gross LTV = monthly revenue per customer times gross margin, divided by monthly churn rate.
Free calculator
LTV:CAC Calculator
Estimate CAC, gross customer lifetime value, payback period, and LTV:CAC ratio for SaaS or recurring-revenue offers.
Inputs
Use acquisition spend, new customers, average monthly revenue per customer, gross margin, and monthly churn. Keep paid, sales, and founder-led acquisition separate when possible.
Interpretation
A strong ratio with slow payback can still strain cash. Trust leaks in pricing, proof, onboarding, and risk reversal often show up as weak conversion or churn.
Worked Examples
Self-Serve SaaS
A product spends $7,500 to acquire 50 customers. Each pays $99/month at 80% gross margin with 5% monthly churn. CAC is $150, gross LTV is $1,584, and LTV:CAC is 10.6x.
Decision: the ratio is strong, but check whether churn is measured on mature cohorts before scaling.
Sales-Led Offer
A team spends $12,000 to win 12 accounts. Each pays $300/month at 70% margin with 8% churn. CAC is $1,000, gross LTV is $2,625, and payback is 4.8 months.
Decision: improve demo-page proof and pricing confidence if CAC rises.
Ratio And Payback Interpretation
| Signal | Watch For | Next Action |
|---|---|---|
| LTV:CAC below 1x | Acquisition cost is higher than gross lifetime value. | Stop scaling and diagnose offer, targeting, pricing, churn, or conversion trust. |
| LTV:CAC near 3x | Often a workable target if payback and retention are stable. | Improve page proof and onboarding before adding more channels. |
| Long payback | Cash can tighten even with a healthy ratio. | Raise activation, annual prepay, close rate, or pricing confidence. |
Common LTV:CAC Mistakes
Using Inflated Lifetime Value
- Calculating LTV from early customers before churn stabilizes.
- Ignoring gross margin and support or delivery cost.
- Using annual contract value when expansion and retention are unproven.
Blending Acquisition Channels
- Mixing paid ads, founder referrals, partners, and outbound into one CAC.
- Hiding sales labor or onboarding cost outside the model.
- Comparing channels without matching buyer intent and time horizon.
FAQ
What is a good LTV:CAC ratio?
Many teams use 3:1 as a rough healthy target, but the right ratio depends on payback speed, margin, cash position, retention, and growth stage.
How do I calculate CAC payback?
CAC payback is customer acquisition cost divided by gross monthly revenue per customer. It estimates how many months are needed to recover acquisition spend.
Should founder time be included in CAC?
For operating decisions, track founder-led, sales-led, and paid acquisition separately. Blending them can hide which channel is actually scalable.