Use when building unit economics models, financial projections, or analyzing the business viability of a feature or product
When evaluating whether a business decision makes financial sense — new product, pricing change, market expansion, or funding round preparation.
For a SaaS or marketplace, calculate:
Build a bottoms-up model:
New MRR = New customers × ARPU
Expansion MRR = Existing customers × upsell rate × upsell ARPU
Churned MRR = Churning customers × their ARPU
Net New MRR = New + Expansion - Churned
3 scenarios: pessimistic, base, optimistic (vary growth rate assumption)
Fixed: salaries, infrastructure, office Variable: hosting (per user), payment processing fees, customer support cost per ticket Model cost per unit at different scale points (100, 1K, 10K customers)
Break-even = Fixed costs / (Revenue per unit - Variable cost per unit) When does the model become profitable at current growth rate?
Identify the top 3 assumptions that most affect the outcome: