Burn rate is the metric that keeps startup founders awake at night.
It's the rate at which your company is spending cash, and it determines how long until you run out of money. Understanding burn rate is the difference between a startup that runs out of cash at an inopportune moment and one that plans ahead.
Every founder should know their burn rate like they know their product. It's the simplest predictor of whether your startup will survive.
Definition
Burn rate is the rate at which a company spends cash, typically measured monthly. It's the total cash outflows (expenses) minus total cash inflows (revenue).
Net burn rate (most important): Total monthly expenses minus revenue. Gross burn rate (early-stage): Total monthly expenses (ignoring revenue).
The Formulas
Monthly Burn Rate:
Net Burn Rate = Total Monthly Expenses - Total Monthly Revenue
Gross Burn Rate (early-stage):
Gross Burn Rate = Total Monthly Expenses
Monthly Runway (months until you run out of cash):
Runway = Cash on Hand ÷ Monthly Net Burn Rate
Examples
Example 1: Early-Stage Startup (Pre-Revenue)
- Monthly salary expenses: $50,000
- Monthly infrastructure/tools: $5,000
- Monthly marketing: $10,000
- Monthly miscellaneous: $5,000
- Revenue: $0
- Gross Burn Rate = $70,000/month
- Cash in bank: $500,000
- Runway = $500,000 ÷ $70,000 = ~7.1 months
Example 2: Revenue-Stage Startup
- Monthly expenses: $100,000
- Monthly revenue: $30,000
- Net Burn Rate = $100,000 - $30,000 = $70,000/month
- Cash in bank: $700,000
- Runway = $700,000 ÷ $70,000 = 10 months
Example 3: Growing Company (Path to Profitability)
- Monthly expenses: $500,000
- Monthly revenue: $400,000
- Net Burn Rate = $500,000 - $400,000 = $100,000/month
- Cash in bank: $2,000,000
- Runway = $2,000,000 ÷ $100,000 = 20 months
As revenue grows and approaches expenses, runway extends dramatically.
Gross vs. Net Burn Rate
| Metric | Definition | When to Use | Example | |--------|-----------|------------|---------| | Gross Burn | Total monthly expenses (all cash out) | Pre-revenue startups, understanding fixed costs | $100K expenses = $100K gross burn | | Net Burn | Expenses minus revenue | Revenue-generating companies, tracking sustainability | $100K expenses - $40K revenue = $60K net burn |
Why it matters: A startup with $100K gross burn and $50K revenue has a $50K net burn—a much healthier position than the gross burn suggests.
However, tracking gross burn is useful for understanding what your fixed costs are. If gross burn is $100K/month, you need at least that much revenue to break even.
Runway Calculation
Runway is the most important metric derived from burn rate:
Runway (months) = Cash on Hand ÷ Net Monthly Burn Rate
What runway tells you:
- 24+ months: Comfortable. You have time to find product-market fit.
- 12-24 months: Healthy. Most VCs expect this post-Series A.
- 6-12 months: Tight. You need to raise more capital or reach profitability soon.
- <6 months: Critical. You're out of time; fundraising is urgent.
Reality check: Most investors want to see you reaching profitability (net burn = 0) or close to it. Venture capital is for scaling, not just surviving longer.
Fixed vs. Variable Burn
Understanding your burn composition helps you forecast and plan:
Fixed Burn (doesn't scale with revenue):
- Salaries
- Rent
- Insurance
- Core infrastructure
Variable Burn (scales with customers/revenue):
- Customer support costs
- COGS (cost of goods sold)
- Payment processing fees
- Hosting/servers (often)
Most startups have high fixed burn, which means:
- In early stages, you burn lots regardless of progress
- As you add revenue, net burn decreases (good)
- If you cut spending, fixed costs drop slower than variable costs
Industry Benchmarks
Burn rates vary widely by:
- Stage: Seed startups burn $50K–$150K/month; Series A burn $100K–$500K/month
- Industry: FinTech/biotech burn more than B2C software
- Geography: San Francisco is expensive; Eastern Europe is cheap
However, the benchmark that matters is: Can you raise capital before your runway ends? Most VCs expect you to close a round 6–9 months into your 12–18 month runway.
How to Reduce Burn Rate
1. Cut non-essential expenses
- Move to cheaper office space or go remote
- Cut paid tools you don't actively use
- Negotiate software contracts
- Review vendors regularly
2. Reduce headcount strategically
- Hiring is the biggest cost for most startups
- Before hiring, ask: "Is this person essential to reach product-market fit?"
- Contractors can be cheaper than employees for specialized roles
3. Outsource expensive functions
- Customer support via call centers
- Accounting/bookkeeping
- Design/development if not core to your product
4. Optimize fixed costs
- Negotiate rent
- Share office space
- Consolidate software platforms
5. Increase revenue (best solution)
- This lowers net burn without cutting costs
- Focus on high-value customers
- Increase pricing (lower CAC, higher lifetime value)
6. Change your business model
- If B2C is burning fast, try B2B (higher ACV, longer sales cycle)
- If you're spending on infrastructure, try SaaS model (recurring revenue)
Common Mistakes
1. Only tracking gross burn Gross burn is useful, but ignores revenue. As you scale, revenue growing faster than expenses is the real win.
2. Assuming burn rate is static Burn rate changes with hiring, spending decisions, and revenue growth. Forecast scenarios with different hiring plans.
3. Not accounting for seasonal variations Marketing spend might increase in Q4, or revenue might dip in summer. Use 3–6 month average, not just last month.
4. Forgetting to include benefits/taxes Actual salary cost is 30–40% higher than base salary (benefits, payroll taxes, workers comp).
5. Not updating burn rate frequently Recalculate burn rate monthly. Use it to forecast and adjust spending as conditions change.
Burn Rate and Fundraising
Burn rate determines your fundraising urgency:
If you have:
- 24 months runway → You can be selective about fundraising terms
- 12 months runway → Start fundraising conversations
- 6 months runway → Close a round now
- <3 months runway → You're in a weak negotiating position
Most venture deals take 3–6 months to close. If your runway is 12 months and you spend 6 months fundraising, you need to close with 6 months remaining.
Related Metrics
- Runway — Months until you run out of cash
- Customer Acquisition Cost — Cost to acquire customers (impacts burn)
- Monthly Recurring Revenue — Revenue to offset burn
- Churn Rate — How much revenue you lose (impacts net burn)