Finance and Product read the same data as LTV/CAC = 4 and as a loss — find the disagreement.
Finance and Product both analyzed the same paid channel and disagree flatly: Finance reports LTV/CAC = 4 and calls it clearly profitable, while Product says every customer loses money. No numbers were faked — they used the same customers and the same CAC.
Shared inputs: AOV 5000 ₽ · 4 orders over life · CAC 5000 ₽ · gross margin 25%
payment fees + support + refunds ≈ another 15% of revenue
Finance LTV = 5000 × 4 = 20000 ₽ → LTV/CAC = 20000 / 5000 = 4.0
Product LTV = 20000 × 0.25 = 5000 ₽ → minus ~15% of revenue → ~2000 ₽
→ LTV/CAC = 2000 / 5000 = 0.4Explain why the two numbers diverge and which one is right. Diagnose the cause.
Finance put gross revenue in LTV's numerator; Product used contribution margin. LTV must rest on margin, not revenue — after a 25% gross margin and ~15% of revenue lost to fees, support, and refunds, net contribution is ~2000 ₽, so the true LTV/CAC ≈ 0.4, not 4. Product is right.
- ✗Building LTV on gross revenue instead of contribution margin
- ✗Assuming variable costs like fees and refunds sit inside CAC
- ✗Trusting a headline LTV/CAC without checking the numerator's basis
- →Which variable costs must the LTV numerator net out?
- →How would you standardize one LTV definition across teams?
Both sides compute LTV but put different things in the numerator. Recompute on one definition:
Shared inputs: AOV 5000 ₽ · 4 orders over life · CAC 5000 ₽ · gross margin 25%
payment fees + support + refunds ≈ another 15% of revenue
Finance LTV = 5000 × 4 = 20000 ₽ → LTV/CAC = 20000 / 5000 = 4.0 (revenue)
Product LTV = 20000 × 0.25 = 5000 ₽ → minus ~15% of revenue (3000 ₽) = 2000 ₽
→ LTV/CAC = 2000 / 5000 = 0.4 (margin)Finance put gross revenue in the LTV numerator. But LTV must be built on contribution margin: after a 25% gross margin and another ~15% of revenue for fees, support, and refunds, net contribution per customer is ≈ 2000 ₽. The real LTV/CAC ≈ 0.4 — the channel loses money. Product is right: the headline LTV/CAC = 4 only holds because revenue, not margin, sits in the numerator.
