unit-economicslisted

# Unit Economics (LTV/CAC and Cohorts) ## When to use Use when you need to know whether a customer is worth more than it costs to acquire: CAC, gross-margin contribution, retention, LTV, the LTV/CAC ratio, and CAC payback in months. Good for SaaS and subscription businesses, board reviews, and diligence where a cohort retention grid backs the headline ratios. The skill builds a downloadable .xlsx in the Claude app with openpyxl; it does not use any Excel add-in or Microsoft 365 connection. ## What it builds A workbook with six tabs: - Cover: title, color legend, scenario selector, headline LTV/CAC and payback. - Assumptions: blue inputs (S&M spend, new customers, ARPU, gross margin %, churn, discount rate, scenario multipliers). - Cohorts: a retention grid, cohorts down the rows and months across the columns, with retained % and revenue per cohort. - Unit Economics: CAC, ARPU, contribution per customer, payback. - LTV-CAC: LTV by the simple formula and by discounted cohort contribution, plus the ratio. - Checks: consistency, monotonic retention, and payback sanity flags. ## Build workflow 1. Create the workbook and the six tabs in the order above. 2. On Assumptions, lay out all inputs in blue with units; add a scenario cell (1=Base, 2=Bull, 3=Bear) named `scn`. 3. Build CAC and per-customer contribution on Unit Economics from the spend and customer inputs. 4. Build the cohort grid: a month-0 base of 100% (or starting customers) decaying by retention across months. 5. Add a