Business Finance Hub

Methodology · Operating Finance

Operating finance calculator methodology

Reviewed by · Last reviewed .

1. Overview

The operating-finance category covers the calculators an operator opens before a board meeting, a fundraise, or a hiring decision: cash runway, CAC + LTV + payback, cap table + dilution, business valuation, break-even, and working capital.

What these share: the math is simple, the inputs are the operator's own data, and the value is in the framing — default-alive vs default-dead, ratio vs payback, post-money SAFE conversion vs pre-money round, DCF vs multiple. Every calculator surfaces the framing alongside the number so operators don't optimize for a single metric in isolation.

2. Primary sources

  • Paul Graham, "Default Alive or Default Dead?" (2015). The canonical framing for the runway classification rule used in the cash-runway calculator. A company is "default alive" if, at its current growth rate, revenue will exceed burn before cash runs out. paulgraham.com/aord.html
  • David Sacks, "The Burn Multiple." Burn multiple = net burn ÷ net new ARR. The original public framing of the metric. Used in the runway calculator alongside default-alive to give two complementary lenses on capital efficiency.
  • David Skok, "SaaS Metrics 2.0" (2017). The canonical operator framing for CAC, LTV, LTV:CAC ratio, and CAC payback period. forentrepreneurs.com
  • Bessemer Venture Partners, State of the Cloud. The annual benchmark report from which we draw the LTV:CAC ≥ 3 and CAC-payback ≤ 12-18-month tier thresholds used in the customer-economics calculator. bvp.com/atlas
  • Aswath Damodaran, NYU Stern industry datasets. Source of industry revenue and EBITDA multiples used in the valuation calculator's comparable-multiples method. pages.stern.nyu.edu/~adamodar
  • McKinsey, Valuation: Measuring and Managing the Value of Companies. The standard DCF framing — explicit projection period plus Gordon-growth terminal value — that the valuation calculator implements.
  • Y Combinator post-money SAFE. The cap-table calculator implements the YC post-money SAFE convention with the standard Safe User Guide rules for valuation cap and discount. ycombinator.com/documents
  • Garrison/Noreen/Brewer, Managerial Accounting. Standard reference for break-even, contribution margin, margin of safety, and working-capital cycle (DSO, DIO, DPO, CCC).

3. Formula derivations

Cash runway, classification, and burn multiple. Runway in months = current cash ÷ monthly net burn, where net burn = monthly burn − monthly revenue. Default-alive evaluates whether revenue at the supplied growth rate exceeds burn before cash zeros out; the calculator returns "default alive," "default dead," or "ambiguous" (the last only when no revenue signal is provided). Burn multiple uses month-1 net new revenue (monthly revenue × growth rate) as the denominator.

Customer economics. CAC = sales-and-marketing spend ÷ new customers acquired in the period. LTV (basic) = ARPU × gross margin × (1 ÷ monthly churn). NRR-adjusted LTV swaps the churn assumption for net revenue retention to credit expansion revenue. CAC payback = CAC ÷ (ARPU × gross margin), reported in months. Magic number = 4 × QoQ ARR delta ÷ prior-quarter S&M spend.

Cap table + dilution. Post-money SAFE conversion follows the YC convention: SAFE shares = investment ÷ effective conversion price, where the price is the lower of (a) cap ÷ post-money fully diluted shares and (b) priced round price × (1 − discount). Subsequent priced round dilutes everyone, including the SAFE-converted holders.

Business valuation. DCF uses an explicit projection period plus a Gordon-growth terminal value, discounted at a single rate. Multiples method applies a revenue or EBITDA multiple drawn from the Damodaran industry dataset. Comparable-transactions method takes a caller-supplied array of recent comp deals and returns the median revenue-multiple ratio applied to current revenue. The point isn't any single number — it's the spread between the three methods, which is the insight an M&A negotiation has to span.

Break-even. Break-even units = fixed costs ÷ (price − variable cost per unit). Margin of safety = (current sales − break-even sales) ÷ current sales. Contribution margin ratio = (price − variable cost) ÷ price.

Working capital. NWC = current assets − current liabilities. DSO = AR ÷ revenue × days. DIO = inventory ÷ COGS × days. DPO = AP ÷ COGS × days. Cash conversion cycle = DSO + DIO − DPO. Negative-CCC businesses (DPO > DSO + DIO) are float-financed by their suppliers; the calculator flags this explicitly.

4. Edge cases and assumptions

  • Runway with seasonal revenue. The calculator uses a single growth rate. Highly seasonal businesses (Q4-heavy retail, summer-camp economics) should run the calc multiple times against trough months, not annual averages.
  • LTV with high NRR. For SaaS businesses with NRR > 100%, the basic LTV formula understates the metric significantly. The NRR-adjusted variant corrects for this but caps at a finite horizon — infinite-LTV companies are mathematically a fixed point that operators should evaluate skeptically.
  • SAFE stacking. The cap-table calculator handles a single SAFE plus a priced round. Multiple stacked SAFEs at different caps and discounts require an extended model; we surface this as an explicit limitation rather than producing a misleading single answer.
  • DCF terminal-value sensitivity. Terminal value typically represents 60-80% of total DCF value, and is highly sensitive to the discount-rate / terminal-growth spread. The valuation calculator returns a single point estimate; sensitivity tables are a v2 feature.
  • Asset-based valuation. Not modeled. For asset-heavy businesses (real estate, equipment- heavy services), DCF and multiples both understate value relative to liquidation or replacement-cost methods.

5. Update protocol

Operating-finance calculators are reviewed quarterly and updated on these triggers:

  • Damodaran publishes the annual industry dataset refresh (typically January).
  • Bessemer publishes the State of the Cloud benchmark update.
  • Y Combinator updates the post-money SAFE template or User Guide.
  • A material methodological correction is identified in a primary source we cite.

Material errors are documented on the corrections page.

6. Limitations

These calculators are estimates for educational use. They do not replace a board-grade financial model, a Quality of Earnings analysis, or qualified counsel on equity financings. SaaS metric tier thresholds are heuristics drawn from venture-funded SaaS benchmarks; bootstrapped operators, services businesses, and e-commerce companies should treat them as orientation rather than targets.

7. Reviewer

Reviewed by Byron Malone, Founder, Bedrocka Tools. Operator background spans cash-runway modeling through more than one cycle, term-sheet negotiation, and SaaS-metric review on real operating businesses. Read the full bio at /authors/byron-malone.

8. Last reviewed

. Reviewed against Skok 2017, Bessemer State of the Cloud (most recent), Damodaran NYU Stern dataset (most recent annual release), and the YC post-money SAFE template (current published version). Bedrocka Tools follows documented editorial standards.