Runway (Months)

Rogue ID: finance.runway_months Type: Number (months) Domain: Finance

Definition

Estimated number of months the company can operate at the current net burn before unrestricted cash reaches zero, holding everything else constant. The single most consequential survival input for venture-backed companies — it sets the urgency of every fundraising, hiring, and cost decision. Common pitfall: runway is often quoted off finance.total_cash_in_bank and a single-month spot-burn instead of operationally-available cash and a 3-month-trailing burn — the result is a runway that looks 2–4 months longer than it actually is when working capital tightens. Boards should ask which cash and which burn went into the calculation.

Formula

runway_months = cash_basis / finance.net_burn_rate, where cash_basis is finance.operationally_available_cash when working capital is material (Series A+), and finance.total_unrestricted_cash otherwise (early stage, when AR/AP is immaterial and the two converge). Never use max() of the two — that discards the more conservative number exactly when working capital is a headwind, the very pitfall this KPI warns about. When net burn is negative (cash-flow positive), runway is unbounded — render as ∞ rather than negative. Most boards use a 3-month-trailing-average net burn for the denominator to dampen single-month noise.

Why it matters

Drives the timing of every fundraise, hire, and budget cut — and is the number investors lead with in diligence. Crossing under stage-typical thresholds usually triggers a board-level cost or fundraising conversation.

How to interpret

Stage-typical industry context (per the 2024 KeyBanc Capital Markets & Sapphire Ventures SaaS Survey §runway / month-of-cash discussion): private SaaS companies with $10M–$50M year-end ARR median ~25 months of cash; those <$10M or >$50M ARR median ~18 months. Practitioner heuristics (industry folk-wisdom, not citation-grade): under 6 months is critical (immediate fundraise or cost action); 12–18 months is healthy for active fundraising; 24+ months gives optionality. Recalculate any time burn changes materially or a tranche closes.

Calculation policy

How an AI agent should compute this KPI from messy company data. Free-text rules consumed at reasoning time — not a deterministic DSL. The most common ways to get this wrong are listed under Common miscomputations.

Inclusion rules

• Numerator: at growth stage (Series A+) use finance.operationally_available_cash. At early stage, finance.total_unrestricted_cash is acceptable when AR/AP are immaterial.
• Denominator: finance.net_burn_rate on a trailing-3-month-average basis. Match the smoothing window used in the burn calculation.
• Result is in months. Express to one decimal place when ≥ 6; whole months when < 6 (decimals at sub-6-month runway suggest false precision).

Exclusion rules

• Restricted cash from the numerator (collateral, escrow, customer-prepaid-restricted balances).
• Undrawn credit facilities or venture-debt capacity — those are funding capacity, not runway. List separately as "available capital outside runway."
• Equity raises in process but not closed. Runway is a backward-looking metric; pending fundraises go in the fundraising-strategy KPI, not here.

Required inputs

• Operationally-available (or unrestricted) cash for the period close.
• Trailing-3-month net burn rate.
• Methodology flag: which cash definition and which burn smoothing window were used.

Data-source priority

• Audited or reviewed cash balance + a closed-period burn calculation.
• Treasury-system cash + FP&A burn forecast as a fallback — flag uncertainty.

Edge cases

• Negative net burn (cash-flow positive): runway is mathematically unbounded. Render as "∞" or "cash-flow positive" — never a negative or null number.
• Net burn very close to zero (break-even): runway becomes hyper-sensitive to denominator noise. Use a wider smoothing window (6-month) or flag the runway as "approaching breakeven, not meaningful as a single number."
• Pending tranche close: typical practice is to compute runway both with and without the expected tranche, label clearly.
• Material foreign-currency cash: convert to reporting currency at a stable rate and disclose the conversion.

Validation checks

• Result is positive (or infinity). A negative or NaN runway indicates a bug — most often a negative cash balance or a zero burn.
• Recompute monthly; runway should change roughly linearly with elapsed time when burn is stable. Step-function jumps usually mean the burn smoothing window slid or a tranche closed.
• Cross-check against stage-typical KBCM bands (~25 months for $10–50M ARR, ~18 months below or above). Out-of-band runway is more often a calculation issue than a real outlier.

Common miscomputations

• Using total cash (including restricted) in the numerator — overstates runway by the restricted balance.
• Using a single-month spot burn instead of a trailing average — runway whipsaws on monthly noise; boards see "we lost 4 months of runway in a month" when it's just a lumpy outflow.
• Mixing unrestricted-cash numerator with operationally-available-cash burn (or vice versa) — definitions must agree on what cash is being depleted.
• Counting undrawn venture debt as "runway" — boards see ~6 extra months of runway that aren't actually deployable without drawing the facility (which itself takes weeks and has covenants).
• Reporting runway from total cash but using a burn that already includes financing inflows — double counts and reads ~2x longer than reality.

Related KPIs

• finance.total_cash_in_bank
• finance.total_unrestricted_cash
• finance.operationally_available_cash
• finance.net_burn_rate
• finance.burn_rate_scenarios
• fundraising.target_raise

Source

KBCM/Sapphire SaaS Survey 2024 (15th Annual) · section: Months of Cash (Runway) by ARR Cohort — published 2024-09-01.

Why does this cite KBCM/Sapphire SaaS Survey 2024 (15th Annual)? Read the ontology methodology for the published vs editorial tier system, attribution rules, and dispute process.

Stage relevance

Suggested for stages: Pre-Seed, Seed, Series A, Series B.

Default owning functions

• Finance

Machine-readable

• This KPI as JSON: /api/ontology/finance/runway_months.json
• All Finance KPIs: /api/ontology/finance.json
• Full catalog: /api/ontology/index.json