{"schema":"askedwell-answer-v1","url":"https://askedwell.com/pages/what-is-the-difference-between/burn-and-runway","question":"What is the difference between burn rate and runway?","short_answer":"Burn rate is how fast you SPEND money (cash out, $/month). Runway is how long you SURVIVE on current cash (months until $0). Burn × runway = total cash. A startup with $500k cash and $50k/mo burn has 10 months of runway. Net burn (spending − revenue) is the more useful number than gross burn.","long_answer":"**The two metrics defined**\n\nBoth metrics describe the relationship between cash spent + cash available. They're sides of the same coin.\n\n- **Burn rate** — monthly cash outflow. Gross burn = total monthly expenses. Net burn = expenses minus revenue.\n- **Runway** — months until cash hits $0. Formula: Current cash / Monthly net burn.\n\nExample: $1M in the bank, spending $80k/mo, earning $30k/mo. Net burn = $50k/mo. Runway = 20 months.\n\n**Side-by-side comparison**\n\n| Property | Burn rate | Runway |\n|---|---|---|\n| Unit | $/month (e.g., $50,000/mo) | Months (e.g., 18 months) |\n| What it measures | Spending velocity | Time until insolvency |\n| Direction | Higher is WORSE | Higher is BETTER |\n| Formula | Gross: total spend / month. Net: (spend − revenue) / month | Cash / Net burn |\n| Trends | Should DECREASE if maturing | Should STAY ≥12 months for safety |\n| Reaction lever | Cut spending, raise revenue | Raise money, cut burn, OR grow revenue |\n| Time-frame | This-month / quarter | Forward-looking, planning horizon |\n| Investor question | \"What's your burn?\" | \"How much runway do you have?\" |\n| Common trap | Reporting gross when net is what matters | Calculating with revenue that hasn't materialized |\n\n**Gross burn vs net burn**\n\n- **Gross burn** = total monthly outflow. Salaries + rent + cloud + tools + everything.\n- **Net burn** = gross burn − monthly revenue.\n\nA company spending $100k/mo and earning $40k/mo has $60k net burn. Net burn is the operationally relevant number — that's what depletes cash. Gross burn is the worst-case if revenue dries up.\n\nWhen founders say \"I'm burning $60k/mo\" they usually mean net burn. When investors ask, they often want both.\n\n**Why net burn is more useful**\n\nTwo companies with identical $100k/mo expenses:\n- Company A: $0 revenue. Net burn = $100k/mo. With $1M cash: 10 months runway.\n- Company B: $80k/mo revenue. Net burn = $20k/mo. With $1M cash: 50 months runway.\n\nSame gross burn; 5× difference in runway. Net burn captures business reality.\n\n**Runway thresholds (calibrated against venture norms)**\n\n| Runway | Verdict | Action |\n|---|---|---|\n| <6 months | Critical | Raise money NOW (assume 3-6 months to close) or aggressive cost cuts |\n| 6-12 months | Watch carefully | Optimize burn; start raising 9 months before $0 |\n| 12-18 months | Healthy | Default startup runway; raise when ready, not from desperation |\n| 18-24 months | Strong | Ample buffer; can survive bad market |\n| 24+ months | Excellent | Capital-efficient growth or over-capitalized |\n\nThe 18-month benchmark (David Sacks, Brad Feld, others) is canonical: gives 12 months to operate + 6 months to raise.\n\n**Burn multiple — the modern unit-economics metric**\n\nBurn multiple = Net Burn / Net New ARR added in same period. Lower = more capital-efficient growth.\n\n| Burn multiple | Verdict |\n|---|---|\n| <1× | Best-in-class (rare; usually only at scale) |\n| 1-2× | Healthy growth (gold-standard early/mid stage) |\n| 2-3× | Acceptable (typical for high-growth Series A-B) |\n| >3× | Inefficient growth; burning more than producing |\n\nIf you burn $1M to add $500k Net New ARR, burn multiple = 2×. That's reasonable. If you burn $1M to add $200k ARR, burn multiple = 5×. Investigate before next raise.\n\n**Common burn/runway mistakes**\n\n- **Optimistic revenue projections** — calculating runway using expected revenue that hasn't materialized; use trailing-3-month average revenue\n- **Excluding one-time costs** — runway based on \"normalized\" burn excluding \"one-time\" items that keep appearing as new \"one-time\" items\n- **Ignoring funding-round closure timing** — assuming you close a round on day 1 of approaching $0; realistic is 3-6 months\n- **Not tracking by-segment burn** — engineering burn vs sales burn vs marketing burn; cutting one is different from cutting another\n- **Currency exposure** — multi-currency operations + FX rate swings affect runway materially\n\n**The classic \"default alive vs default dead\" framing**\n\nPaul Graham 2015 essay: a startup is \"default alive\" if current revenue growth would make it profitable before cash runs out, otherwise \"default dead.\" Most startups are default dead and don't realize it. Quick check:\n\n- If you stopped raising tomorrow + your current revenue growth continued + your costs stayed flat — would you reach profitability before $0?\n- Yes = default alive\n- No = default dead (need to raise OR cut costs OR accelerate revenue)\n\nThe exercise forces honest evaluation of whether your business model works without external capital.\n\n**Cross-reference:** see /pages/what-is/customer-acquisition-cost + /pages/what-is/monthly-recurring-revenue + /pages/what-is-the-difference-between/cac-and-ltv.","duration_iso":"PT0M","ranges":[{"condition":"Critical runway (<6 months)","duration":"Raise immediately or cut aggressively"},{"condition":"Default healthy runway","duration":"12-18 months (canonical startup benchmark)"},{"condition":"Strong runway","duration":"18-24 months"},{"condition":"Time to raise a round","duration":"3-6 months from start to wire"},{"condition":"Healthy burn multiple","duration":"<2× (Net Burn / Net New ARR)"}],"variables":[{"name":"Gross vs Net burn","effect":"Gross excludes revenue. Net = Gross − Revenue. Net is operationally relevant; Gross is worst-case planning"},{"name":"Revenue assumption stability","effect":"Trailing-3-month revenue average more reliable than forward-looking. Optimistic revenue assumptions destroy runway calculations"},{"name":"Cost variability","effect":"\"One-time\" costs that keep appearing are actually recurring; runway calculations using normalized burn often understate true burn by 10-30%"},{"name":"Funding-round timing","effect":"Assume 3-6 months to close a round. Start raising at 9-12 months runway, not at 3 months desperation-level"}],"sources":[{"label":"Paul Graham, \"Default Alive or Default Dead?\"","tier":2,"url":"https://www.paulgraham.com/aord.html","note":"Canonical essay on startup burn-vs-runway thinking"},{"label":"Brad Feld, \"Burn Rate Discipline\"","tier":2,"url":"https://feld.com/archives/category/business-stuff/","note":"Founder-investor framework for burn/runway management across stages"},{"label":"Bessemer Venture Partners \"Burn Multiple\"","tier":1,"url":"https://www.bvp.com/atlas/state-of-the-cloud-2024","note":"Burn multiple as the modern capital-efficiency metric; benchmarks by stage"},{"label":"David Sacks, \"How to Manage Your Burn\"","tier":2,"url":"https://medium.com/craft-ventures/the-burn-multiple-9e94358f1ade","note":"Origin of the Burn Multiple framework; comparison to traditional cash-burn metrics"},{"label":"YC Startup School curriculum","tier":2,"url":"https://www.startupschool.org/","note":"Standard runway calculation methodology + raise-timing guidance for early-stage founders"}],"faq":[{"question":"What's a \"good\" burn rate?","answer":"There's no universal number — it's relative to your funding and runway. $50k/mo burn is great if you have $5M in the bank (8+ years runway) and disastrous if you have $200k (4 months). The question is always \"burn relative to runway.\" Healthy: burn that gives 12-18 months runway WITH realistic growth assumptions. Investors evaluate burn multiple (Net Burn / Net New ARR) more than absolute burn — efficiency matters more than spending level."},{"question":"When should I start raising my next round?","answer":"When you have 9-12 months of runway, not when you have 3. Reasons: (1) Fundraising typically takes 3-6 months from first meeting to wire. (2) Raising from a position of strength (still 6 months runway when closing) yields better terms than raising from desperation. (3) Market conditions can shift quickly — having buffer time means you can wait for favorable conditions instead of accepting any terms. The phrase \"raise when you don't need to\" is canonical for this reason."},{"question":"How do I reduce burn without hurting growth?","answer":"Three highest-leverage moves: (1) Audit cloud + SaaS tool spend — most companies overspend by 20-40% on tools. Quarterly audit recovers significant burn. (2) Slow hiring — extending time-to-hire by 30 days conserves cash without reducing existing capacity. (3) Renegotiate vendor contracts at renewal — 10-20% discounts common when threatening to leave. AVOID: cutting marketing (kills growth flywheel); cutting engineering (kills product velocity); freezing customer support (kills retention)."},{"question":"What's \"default alive vs default dead\"?","answer":"Paul Graham's framing: would your startup reach profitability before $0 if you stopped raising NEW capital and your current revenue growth continued? Yes = \"default alive\" (you control your destiny). No = \"default dead\" (you depend on raising another round to survive). Most early-stage startups are default dead and don't realize it. The exercise forces honest evaluation: does your business model actually work at scale, or does it only work with infinite cheap capital?"}],"keywords":["burn rate vs runway","difference between burn and runway","startup runway","net burn rate","gross burn rate","how to calculate runway","default alive default dead","burn multiple"],"category":"business","date_published":"2026-05-27","date_modified":"2026-05-27","license":"CC-BY-4.0","attribution":"https://askedwell.com"}