Build a Unit Economics Model to Validate Business Profitability
Build a complete unit economics model with CAC, LTV, payback period, sensitivity analysis, and strategic recommendations.
📝 The Prompt
Act as a financial modeling expert and startup CFO advisor. Build a detailed unit economics model for [COMPANY NAME], a [BUSINESS MODEL TYPE, e.g., subscription SaaS, marketplace, D2C e-commerce, on-demand service] operating in [INDUSTRY].
Business context:
- Average selling price / subscription price: [PRICE]
- Current customer count: [NUMBER]
- Monthly growth rate: [PERCENTAGE]
- Primary customer acquisition channels: [LIST 2-4 CHANNELS]
- Average sales cycle length: [DURATION]
- Gross margin: [PERCENTAGE OR 'UNKNOWN — HELP ME ESTIMATE']
Build the model in these steps:
Step 1 — Customer Acquisition Cost (CAC):
- Break down fully-loaded CAC by channel (paid ads, content/SEO, sales team, partnerships)
- Include often-overlooked costs: sales salaries, tooling, creative production, attribution overhead
- Calculate blended CAC and channel-specific CAC
Step 2 — Lifetime Value (LTV):
- Calculate average revenue per user (ARPU) monthly and annually
- Estimate gross margin per user
- Model customer retention curve and derive average lifespan (use churn rate of [MONTHLY CHURN RATE] or help me estimate)
- Compute LTV using both simple (ARPU × Gross Margin × Lifespan) and DCF-adjusted methods (discount rate: [RATE, e.g., 10%])
Step 3 — Key Ratios & Benchmarks:
- LTV:CAC ratio (target: >3x) — interpret current standing
- CAC payback period in months — flag if exceeding [THRESHOLD, e.g., 12 months]
- Contribution margin per unit/transaction
- Compare against industry benchmarks for [INDUSTRY]
Step 4 — Sensitivity Analysis:
- Show how unit economics change with ±20% variations in: churn rate, ARPU, CAC, and gross margin
- Identify the single variable with the greatest impact on profitability
Step 5 — Strategic Recommendations:
- Provide 5 specific, actionable levers to improve unit economics
- Suggest which metrics to monitor weekly vs. monthly
- Flag any red flags or unsustainable dynamics in the current model
Present all calculations clearly with formulas and assumptions stated explicitly.
💡 Tips for Better Results
Always use fully-loaded CAC that includes salaries and overhead—underestimating acquisition cost is the most common modeling error. Run sensitivity analysis before presenting to stakeholders so you can preempt 'what if' questions. Update your unit economics model monthly in early stages, as small changes in churn compound dramatically over time.
🎯 Use Cases
Founders, CFOs, and finance teams who need to validate business model sustainability, prepare for investor due diligence, or identify levers to reach profitability.