TLDR:
Unit economics measure the revenue and costs associated with a single unit of business — typically per customer — to determine whether a business model is fundamentally profitable.
Key Unit Economics Metrics
Critical unit economics include Customer Acquisition Cost (CAC), Customer Lifetime Value (LTV), Contribution Margin (revenue minus variable costs), Payback Period (time to recover CAC), and Gross Margin. For SaaS, additional metrics include MRR per customer, Net Revenue Retention, and churn rate. Marketplaces track take rate, average order value, and repeat purchase rate.
Why Unit Economics Matter
Strong unit economics are the foundation of sustainable growth. A business with negative contribution margin loses money on every additional customer — scale only accelerates losses. Conversely, a business with positive unit economics improves financially with each new customer, enabling reinvestment in growth. Investors closely examine unit economics to predict whether scaling will lead to profitability.
Unit Economics by Stage
At pre-revenue or early stages, unit economics are projections; investors look for clear paths to positive unit economics. By Series A/B, unit economics should be improving with scale. By growth stage, unit economics should be solidly positive. Deteriorating unit economics at scale is a major red flag for both investors and founders.
References
Unit economics in diligence and documents
Unit economics is where business model meets evidence, and diligence treats it that way: contribution margin per unit recomputed from raw data, cost allocations challenged (is customer support in the unit or below it?), cohort curves tested against the deck’s claims. The definitional questions are the legal questions — when unit metrics anchor earn-outs, tranche conditions or bonus plans, the unit (order, customer, ride, seat-month), the included costs and the data source must be written with accounting precision. The strategic reading matters too: negative unit economics at scale is a financing thesis only while capital believes the curve bends; documents that promise the bend (projections in information memoranda) should be framed as assumptions with risk factors, not warranted facts.