Burn Rate
Burn rate is the monthly pace at which a startup spends cash, split into gross burn (total outflow) and net burn (outflow minus revenue). Founders and investors must keep these two measurements separate. Net burn is the number that determines runway and gets the most investor attention; gross burn is the number that determines how exposed the company is if revenue stops.
The two numbers, with examples:
| Company state | Monthly expenses | Monthly revenue collected | Gross burn | Net burn |
|---|---|---|---|---|
| Pre-revenue | $150K | $0 | $150K | $150K |
| Early revenue | $150K | $50K | $150K | $100K |
| Growth stage | $400K | $300K | $400K | $100K |
| Approaching cash-flow neutral | $500K | $480K | $500K | $20K |
| Cash-flow positive | $500K | $550K | $500K | -$50K (cash growing) |
Why both numbers matter:
Net burn is the one most-used for runway calculation and investor reporting. It reflects the actual cash leaving the bank account each month.
Gross burn is the worst-case picture. If revenue suddenly stopped (major customer churn, market shock, payment freeze), gross burn is what the company would face. Mature CFOs run both, especially in uncertain markets.
Cash burn vs P&L loss: also different things. Cash burn is what's leaving the bank; P&L loss includes non-cash items (depreciation, accruals, stock-based compensation). At venture-backed startups, cash burn matters more for runway; P&L loss matters more for taxes and valuation modeling.
The burn multiple (David Sacks, 2020):
Burn multiple = Net burn ÷ Net new ARR
Popularized by David Sacks at Craft Ventures and now the standard growth-efficiency metric:
| Burn multiple | Rating |
|---|---|
| Under 1x | Best (every $1 of burn produces $1+ of net new ARR) |
| 1x - 1.5x | Great |
| 1.5x - 2x | Good |
| 2x - 3x | Acceptable at growth stage |
| Over 3x | Concerning; needs explanation |
Example: a company burns $500K/month and adds $250K of net new ARR per month. Burn multiple = 2x. Acceptable at Series B; concerning at Series C+.
Why it works: ARR multiples don't capture how much capital was burned to produce the ARR. Burn multiple normalizes for capital efficiency. A 5x ARR multiple company with 1x burn multiple is more capital-efficient than a 10x ARR multiple company with 4x burn multiple, and the burn multiple shows the difference.
Common burn patterns:
Hiring-driven burn: doubles when engineering and GTM hiring kicks in. Predictable, plannable.
Marketing-driven burn: spike during launch campaigns or paid-acquisition tests. Should produce visible revenue lift; if not, cut.
Infrastructure burn: AWS, tooling, software subscriptions. Tends to drift upward without discipline.
Cost-of-revenue burn: hosting, support, partner fees. Should scale sublinearly with revenue at healthy SaaS economics.
What investors watch for:
- Burn trajectory (rising, flat, falling), flat or falling with growth is excellent; rising faster than growth is a yellow flag and one of the most common reasons cited in Why Startups Fail analyses.
- Burn multiple at growth stage.
- Unexplained burn drift, month-over-month burn climbing without a corresponding output.
- Burn vs benchmarks for stage, wildly higher than peers needs justification; lower without lower output needs investigation.
Worked example: cutting net burn from $400K to $250K at a Series A SaaS company. Same starting state across all three levers (a 30-person team, $400K monthly burn, $200K monthly revenue, 8 months of runway). Each lever produces a different $150K monthly burn reduction with different downstream effects.
| Lever | Mechanic | Headcount impact | Time to realize | Revenue risk | New runway |
|---|---|---|---|---|---|
| Hiring freeze plus 4-person reduction | Cut 4 IC roles (avg $30K/mo loaded comp), freeze 6 planned hires | -4 now, -6 planned | 1 month (severance lag) | Low if cuts avoid revenue-generating roles | ~13 months |
| Marketing pull-back | Cut paid acquisition ($120K/mo) plus offshore content ($30K/mo) | 0 | Immediate | High if CAC payback was working; recoverable | ~13 months |
| Vendor renegotiation plus tool consolidation | AWS contract negotiation (-25%), Salesforce downgrade (-40%), kill 6 SaaS tools | 0 | 60-90 days | None | ~13 months |
All three produce the same headline runway extension. The right answer is rarely a single lever; mature finance teams pick a blend so any single downside (revenue dip from marketing cuts, recruiting brand damage from headcount cuts, vendor lock-in from over-aggressive renegotiation) stays bounded. The frame founders should use at burn-cut time: "what's the smallest cut to each category that gets us to the new burn target," not "what's the biggest cut from any single category."
Ryan's Take
Burn is a strategy choice, not an accident. Founders talk about burn like the weather: "we burned $180K last month" as if the money decided to leave. It didn't. You decided what to spend on. Pair every dollar of burn with the milestone it is supposed to buy. If you can't connect the spend to a specific output, that line item is not strategy, it is just expense. Cut it, or own it as a deliberate bet you can defend. The discipline that works: monthly burn review where every category gets evaluated against output (engineering: did we ship the planned roadmap? marketing: did spend convert to leads? GTM: did hiring produce pipeline?). The pattern that fails: burn becomes a flat line nobody questions because "that's what we spend." Output-anchored burn beats habit-anchored burn every time.
What founders get wrong (specific failure mode): Two-cofounder team raises a $3M seed. Hires aggressively in months 2-9, growing from 4 to 14 people. Burn climbs from $80K/month to $310K/month, close to 4x in nine months. Founder is tracking "months of runway" as 24 months at close, but by month 9 it's actually 10 months because burn grew much faster than initial model. Series A milestone (ARR target) isn't hit on time because the team is still ramping. Founder starts the A raise with 10 months of runway and burn that's hard to defend (the burn multiple is 4x because revenue hasn't caught up). Investors discount. The right discipline: model burn growth concurrent with hiring plan; recalculate runway monthly; if burn is growing faster than ARR, slow hiring before runway becomes the problem.
Related: Runway · Burn Multiple · Capital Efficiency · Unit Economics · Bridge Round · Cash Flow
FAQ
What is the difference between gross burn and net burn?
Gross burn is total monthly cash outflow (all expenses). Net burn is gross burn minus monthly revenue collected. Net burn is the more meaningful number for runway and investor reporting because it reflects actual cash leaving the bank account.
What is a burn multiple?
Net burn divided by net new ARR added in the same period, popularized by David Sacks at Craft Ventures. Under 1x is best, 1-2x is great-to-good, 2-3x is acceptable at growth stage, over 3x is concerning. The standard growth-efficiency metric for SaaS.
Should startups try to minimize burn?
Not always. The right burn is the one that buys the most progress toward the next milestone. Cutting burn at the cost of growth often produces a smaller company that still needs to raise, on worse terms. Anchor burn to output, not to a number.
How fast can burn grow before it's a problem?
The discipline rule of thumb: burn growth should track behind hiring-plan ARR growth. If burn doubles while ARR grows 50%, burn multiple is rising and the next raise will be harder. Monthly burn review (every category, every output) is the operational guardrail.
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