Unit Economics Deep Dive
Written by Harry Prabandham
Curated by Rubric Financial
1 / 5
Core Unit Economics Metrics
- Customer Acquisition Cost (CAC) = total sales & marketing spend / number of new customers acquired in the period
- Lifetime Value (LTV) = average revenue per account (ARPA) x gross margin % / monthly churn rate (for subscription businesses)
- LTV:CAC ratio should be at least 3:1 for a healthy business; below 1:1 means you lose money on every customer acquired
- Blended CAC across all channels obscures performance, so calculate CAC by channel (paid, organic, referral) to optimize spend allocation
Related Resources
What Belongs in SaaS COGS and How to Compute Gross Margin
A practical guide to defining SaaS cost of revenue and calculating gross margin correctly, including AI inference costs and benchmarks.
CFO & StrategyB2B Surcharging: Passing Credit-Card Fees to Customers
How SaaS companies can recover credit-card interchange costs on subscriptions, and the legal and commercial tradeoffs of doing so.
CFO & StrategyBusiness Valuation Methods for Startups
An overview of the valuation methodologies used for startups, from 409A compliance valuations to M&A and fundraising contexts.
About the author
Harry PrabandhamFounder & CEO
Founder and CEO of StartupCFO. MBA from Wharton, MS in Computer Science, and decades of experience building and advising venture-backed startups.
More articles by Harry →Related tools and reading
Unit Economics Calculator
Model CAC, LTV, payback period, and contribution margin.
GuideWhat Belongs in SaaS COGS and How to Compute Gross Margin
A practical guide to defining SaaS cost of revenue and calculating gross margin correctly, including AI inference costs and benchmarks.
InsightStartup CFO Digest: Week 36, September 2026
This week's funding environment shows strength at the mega-round level, with AI infrastructure and capital-efficient models commanding multibillion-dollar valuations. However, founders should note that this capital flow is concentrated in late-stage deals with clear unit economics or strategic customer commitments, not distributed across the venture ecosystem. Meanwhile, challenges around SaaS pricing, churn, and valuation velocity are reshaping how founders plan and forecast when raising now.
GlossaryUnit Economics
The revenue and cost per unit of output (customer, transaction, seat).
InsightStartup CFO Digest: Week 35, August 2026
This week's funding landscape reflects a clear bifurcation: specialized capital flowing aggressively into infrastructure, hardware, and AI-native operations, while unit economics and profitability are becoming hard moats for founders competing for investor attention. The parallel acceleration of agentic AI adoption highlights a critical tension between speed-to-value and governance risk that needs to be front-and-center in your financial and operational planning.
GlossaryTender Offer
Structured opportunity for existing shareholders (often employees) to sell shares to incoming investors or the company.
Want this run on your actual numbers?
A fractional CFO can turn what you just read into a board pack, a forecast, and a spending plan built from your own ledger.
Want the full sample as a PDF?
No spam, ever. If the download doesn't start, email us.
Or talk it through:
