CJ Gustafson created Mostly Metrics after working across startup finance roles, including CFO of PartsTech. He later left PartsTech to work on the newsletter and related media full-time. — I’m Going All In.

Visual summary of operating lessons from CJ Gustafson.

Part 1: SaaS Metrics & Unit Economics

  1. On Gross Margin: Gross margin shows what remains after the direct cost of serving customers; a weak margin limits the resources available for other operating work. — Definitive Guide to COGS.
  2. On Burn Rate: Burn must be read alongside cash on hand: spending faster shortens the time available to reach a viable next milestone. — Burning Bad.
  3. On Churn: Retention cohorts help reveal whether customers keep finding value; acquisition alone cannot compensate indefinitely for poor retention. — What Product-Market Fit Feels Like.
  4. On Net Revenue Retention (NRR): Net dollar retention combines expansion, contraction, and churn among existing customers, though companies do not always calculate it identically. — How Public Companies Calculate NDR.
  5. On The Rule of 40: The Rule of 40 combines growth with a profitability measure, but its interpretation depends on which profit or cash-flow measure is used. — The Right Way to Calculate Rule of 40.
  6. On CAC Payback: CAC payback estimates how long gross profit from a customer takes to recover the cost of acquiring that customer. — CAC Payback Period.
  7. On LTV: LTV-to-CAC can be sensitive to uncertain lifetime and margin assumptions; it should not be treated as a precise operating truth. — Is LTV to CAC the Nickelback of Metrics?.
  8. On Reading the Magic Number: The Magic Number blends new sales, expansion, and churn, so a threshold alone is not a reliable permission slip to increase sales spending. — Is the Magic Number a Bad Party Trick?.
  9. On Deferred Revenue: Advance payments for services not yet delivered are deferred revenue: cash received now, with a remaining obligation to the customer. — Not All Revenue Is Created Equal.
  10. On Professional Services: Implementation services may carry lower margins than software but can still be important to customer adoption and retention. — ServiceTitan IPO Breakdown.

Part 2: The CFO Role & Psychology

  1. On Resource Allocation: A CFO helps allocate scarce resources among competing priorities rather than merely vetoing spending. — What Makes a Great CFO.
  2. On Risk Trade-Offs: A finance leader should make the risks and trade-offs of a decision visible, not pretend a startup can avoid risk altogether. — Managing Investors, Budgets, and Expectations.
  3. On Finance Communication: Strong finance leadership combines analysis with communication so operating partners can use the numbers to make decisions. — What Makes a Great CFO.
  4. On Data Foundations: A reliable finance view depends on consolidating data from different systems before presenting it as a basis for decisions. — What Makes a Great CFO.
  5. On Budgeting: A budget should connect headcount and spending decisions to the company's longer-term goals, and be revisited as conditions change. — Managing Investors, Budgets, and Expectations.
  6. On Being a Business Partner: The CFO's role extends beyond spreadsheets to helping other leaders evaluate choices across the business. — What Makes a Great CFO.

Part 3: Fundraising & Capital Allocation

  1. On Valuation and Dilution: A headline valuation is not the same as an eventual owner or employee payout; dilution and deal terms affect realized proceeds. — Valuation Is a Terrible Scorecard.
  2. On Planning Runway: Gustafson urges venture-backed companies to plan runway deliberately after raising money rather than assume a future round will arrive on demand. — Burning Bad.
  3. On Down-Round Terms: A lower headline valuation can be preferable to a higher one saddled with investor protections that shift the economics of an eventual exit. — You Pick the Valuation, I Pick the Structure.
  4. On Calculating Runway: Runway follows from cash balance and net burn; the original founder-ego explanation is not part of the source. — Burning Bad.
  5. On Venture Expectations: Venture investors seek outcomes large enough to return their funds, so fundraising expectations differ from those of an ordinary profitable small business. — Managing Investors, Budgets, and Expectations.
  6. On Market Tailwinds: Growth during a favorable market can disguise a weak underlying fit; Gustafson cautions against confusing a temporary tailwind with durable demand. — Is Product-Market Fit Getting Harder to Keep?.
  7. On Capital Efficiency: Capital efficiency is about the output a business creates from the capital it consumes; no universal five-to-one enterprise-value formula is asserted here. — CFO’s Guide to Capital Efficiency.
  8. On Board Oversight: The board provides oversight and can replace the CEO when warranted; the CFO normally reports to the CEO while keeping the board informed. — Your Complete Guide to Board Rooms.
  9. On Equity Economics: Employee equity can be valuable, but option holders need to understand dilution, exercise costs, taxes, and the exit waterfall before equating a valuation headline with cash. — Valuation Is a Terrible Scorecard.
  10. On Exit Readiness: A business is more attractive to a potential buyer when its financials, processes, and leadership are ready before an acquisition opportunity appears. — The Exit-Ready Org.

Part 4: Career Advice & Leadership

  1. On Helping a New Boss: Proactively helping a new leader understand the team's context and priorities can make a finance employee more useful; it is not a guaranteed promotion tactic. — How to Make Your New Boss Successful.
  2. On Writing: Gustafson credits sustained writing with helping him explain finance, build an audience, and open career opportunities. — Managing Investors, Budgets, and Expectations.
  3. On Networking: Gustafson found face-to-face meetings unexpectedly valuable for relationships and business opportunities after years of primarily online work. — I Hate How Great IRL Is.
  4. On Hiring Player-Coaches: At an early-stage company, Gustafson values hires who can both do the work and lead others, rather than managers too far removed from execution. — Managing Investors, Budgets, and Expectations.
  5. On Finance Leadership: As finance leaders advance, judgment and the ability to work with other executives matter alongside technical command of the numbers. — What Makes a Great CFO.

Part 5: General Business Wisdom

  1. On Product-Market Fit: Product-market fit becomes more credible when customer behavior shows sustained use and retention rather than only enthusiastic early sales. — What Product-Market Fit Feels Like.
  2. On Sales and PLG: Product-led growth does not remove the need for sales in every market, especially when larger customers require more involved buying support. — Why Romanticizing PLG Is Dangerous.
  3. On Changing Practices as You Scale: As a company grows, finance and hiring practices that worked at an earlier stage need to be revisited for the next stage. — Managing Investors, Budgets, and Expectations.
  4. On Cash Reserves: Maintaining sufficient cash runway gives a company more room to adapt when financing or market conditions turn unfavorable. — Burning Bad.
  5. On AI in Finance: Gustafson sees AI as a way to automate parts of finance work while leaving judgment, controls, and strategic interpretation with people. — When Not to Use AI in Finance.

Part 6: The "2025 Playbook" & AI

  1. On Revenue per Employee: Revenue per employee is a useful efficiency lens, but comparisons need business-model and growth context rather than a universal target. — Revenue per Employee: SaaS vs. VC.
  2. On AI Efficiency: Gustafson expects AI-driven productivity gains to compound and potentially reduce how much outside capital a company needs. — What Worked Episode 31 Transcript.
  3. On Internal AI: Gustafson argues that finance teams should examine internal AI use, not only AI features they might sell to customers. — How CFOs Are Actually Using AI.
  4. On BI and Data Quality: AI-enabled finance analysis still depends on sound data foundations and controlled access; useful BI is more than exporting another spreadsheet. — How CFOs Are Actually Using AI.
  5. On AI and Headcount: Gustafson expects AI to increase the output of finance teams, while cautioning against assuming it makes human staff unnecessary. — What Makes a Great CFO.

Part 7: Advanced SaaS Mechanics (Vertical & Multi-Product)

  1. On Vertical SaaS: A vertical SaaS vendor that owns a central workflow may be able to add adjacent products, increasing revenue per customer and retention. — The Top Metrics for Vertical SaaS.
  2. On Marketplace Take Rates: Marketplace take rates depend on transaction size, frequency, labor intensity, and the value provided; adding services can raise effective monetization, but not automatically. — Comparing Marketplace Take Rates.
  3. On Revenue Leakage: Revenue leakage can arise when contracted usage, billing, and collections diverge; reconciling those systems helps identify missed revenue. — Your Complete Guide to Revenue Leakage.
  4. On "Sales Rep Math": Rep math is a rough capacity check for a sales plan: expected rep productivity and ramp should make the target plausible before the forecast is finalized. — The Importance of Sales Rep Math.
  5. On Outcome-Based Pricing: Outcome-based software pricing ties charges to measurable results rather than simply to seats, but it works best when the outcome can be clearly defined and tracked. — The Age of Outcome-Based Pricing.

Part 8: The CFO as a Storyteller & "Adult in the Room"

  1. The CFO as Resource Allocator: Because people are a major cost and asset in many software businesses, the CFO must weigh hiring and resource allocation carefully. — What Makes a Great CFO.
  2. The CFO as Truth Teller: Gustafson describes the CFO as an honest strategic partner who can challenge a weak product or investment case when the economics require it. — Glasp Talk #48 Transcript.
  3. On Investor Updates: A useful investor update explains the operating story behind the numbers and communicates material changes regularly. — How to Write a Great Investor Update.
  4. The Goalie Metaphor: Gustafson compares a dependable CFO to a goalie who helps keep financial and operating risks from slipping past management. — What Makes a Great CFO.

Part 9: Career & The "Creator-CFO" Transition

  1. The Media Mullet: Gustafson describes his model as media in front and product in back: the newsletter builds an audience for a related benchmarking product. — Growth in Reverse Transcript.
  2. Personal Product-Market Fit: Gustafson uses personal product-market fit for finding work where one's abilities and interests create unusually strong value. — What Worked Episode 31 Transcript.
  3. On Writing into the Abyss: He describes publishing for years with little response before Mostly Metrics developed a substantial audience. — What Worked Episode 31 Transcript.
  4. On Equity Psychology: He recalls the emotions involved in distributing equity proceeds at an exit, including his concern that employees receive a meaningful outcome. — What Worked Episode 31 Transcript.
  1. Your Complete Guide to Revenue Leakage, Mostly Metrics
  2. The Top Metrics for Vertical SaaS, Mostly Metrics
  3. The Importance of Sales Rep Math, Mostly Metrics
  4. Finding “Personal Product-Market Fit”: Career Advice from CJ, Run the Numbers
  5. How CJ Gustafson Grew Mostly Metrics to 60k+ Subscribers (Growth In Reverse transcript)
  6. What Worked Episode 31: Why 65K CFOs subscribe to this ex-CFO's newsletter with CJ Gustafson
  7. How CFOs Are Actually Using AI (Mostly Metrics, CJ Gustafson)
  8. CJ Gustafson: Decode Startup Finance - Metrics, Board Decks & AI Efficiency | Glasp Talk #48