LTV:CAC & CAC Payback
A channel unit-economics model for LTV vs CAC.
It measures CAC, LTV, the ratio, and months to pay back by channel.
Use it to fund the channels that clear payback before you scale spend.
Signal Lab · Model
LTV:CAC & CAC Payback
LTV (lifetime value) vs CAC (customer acquisition cost) by channel — ratio and months to pay back. ACV (annual contract value) / ARPU (average revenue per user) is annual; churn is monthly. Distinct from Lead-to-Revenue and ARR waterfall — this is channel unit economics.
Illustrative AU SaaS / growth sample until you enter actuals. Not financial advice.
Channels, lifetime mode, and thresholds
Up to 4 channels. Persist locally · Jump to metrics
Blended and primary metrics
RAG vs your target LTV:CAC min and payback months max.
Equations
- CAC = Spend ÷ NewCustomers
- LTV (churn) = (ACV÷12) × (GM%÷100) ÷ (monthly churn%÷100) · ACV/ARPU annual · churn monthly
- LTV (lifetime months) = (ACV÷12) × GM% × LifetimeMonths
- Ratio = LTV ÷ CAC · Payback mo = CAC ÷ ((ACV÷12) × GM%)
- Blended CAC = Σspend÷Σcustomers; ACV, GM%, churn customer-weighted
How this is calculated
- CAC (customer acquisition cost) = Channel spend ÷ new customers acquired
- LTV (lifetime value) — churn mode uses monthly contribution ÷ monthly churn; lifetime mode multiplies monthly contribution by fixed months
- ACV (annual contract value) / ARPU (average revenue per user) entered as annual figures
- Payback months = CAC ÷ monthly gross-margin contribution
- Blended totals weight ACV, GM%, and churn by customers
Illustrative channel unit economics — not financial advice.
What-if dials
Monthly churn pts and spend % — live blended ratio and payback.
Churn & spend
Churn shock adds percentage points to every channel’s monthly churn. Spend shock scales every channel’s spend.
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