read-ltv-cac

name	read-ltv-cac
description	Read LTV:CAC against the 3:1 line and contribution margin after the real costs, so a profitability problem is diagnosed correctly. Reach for this on any growth/profit question.

Skill: Read LTV:CAC and contribution margin

Revenue can grow while the unit economics break; this reads the ratio.

Step 1 — Compute CAC by channel

Acquisition spend ÷ new customers, by channel (avg ~$45–$70) (§3 #5).

Step 2 — Compute LTV by cohort

Realized lifetime value per cohort, not a projection.

Step 3 — Read the ratio

LTV:CAC against 3:1 (below 2:1 is urgent) (§3 #1).

Step 4 — Net to contribution margin

Revenue minus COGS, CAC, shipping, returns (§3 #2, #6).

Output

A by-channel CAC, a cohort LTV, the LTV:CAC ratio, and contribution margin after real costs.