Burn Rate & Runway Calculator
Enter your current cash balance, monthly expenses, and monthly revenue. The calculator shows your gross burn (total spend), net burn (spend minus revenue), and exactly how many months of runway remain. Enable optional revenue or expense growth rates to run a month-by-month simulation and see whether your company is default alive — on track to reach profitability before the cash runs out — or default dead.
Verdict
Default Dead
Cash will run out before expenses are covered. Raise revenue, cut costs, or secure more funding.
Gross burn / mo
$80.0k
Total monthly expenses
Net burn / mo
$50.0k
After revenue offset
Runway
10 mo
≈ 0.8 years
Zero cash
May 2027
Estimated depletion date
Cash balance
MonthlyMonth-by-month breakdown
| Mo | Revenue | Expenses | Net burn | Cash |
|---|---|---|---|---|
| 1 | $30,000.00 | $80,000.00 | $50,000.00 | $450,000.00 |
| 2 | $30,000.00 | $80,000.00 | $50,000.00 | $400,000.00 |
| 3 | $30,000.00 | $80,000.00 | $50,000.00 | $350,000.00 |
| 4 | $30,000.00 | $80,000.00 | $50,000.00 | $300,000.00 |
| 5 | $30,000.00 | $80,000.00 | $50,000.00 | $250,000.00 |
| 6 | $30,000.00 | $80,000.00 | $50,000.00 | $200,000.00 |
| 7 | $30,000.00 | $80,000.00 | $50,000.00 | $150,000.00 |
| 8 | $30,000.00 | $80,000.00 | $50,000.00 | $100,000.00 |
| 9 | $30,000.00 | $80,000.00 | $50,000.00 | $50,000.00 |
| 10 | $30,000.00 | $80,000.00 | $50,000.00 | $0.00 |
How it works
Gross burn is the total you spend each month before counting any revenue — it tells you the raw scale of your cost base. Net burn is expenses minus revenue: the actual cash leaving your account after revenue offsets it. A startup with $80 k in monthly expenses and $30 k in revenue has a gross burn of $80 k and a net burn of $50 k. Runway in months is your current cash divided by net burn. When revenue is growing, simple division overstates your remaining time; that is why this calculator runs a month-by-month simulation instead.
The Paul Graham 'default alive or dead' frame asks one precise question: given your current revenue trajectory, will you reach the month where revenue ≥ expenses before your bank account hits zero? Default alive means yes — the business will become self-sustaining without needing another round. Default dead means no — at the current trajectory you will run out of money before covering costs. The verdict matters because it determines whether fundraising is an acceleration or a lifeline.
Monthly compounding growth rates are applied to both revenue and expenses before each period in the simulation. A 5% monthly revenue growth rate compounds to roughly 80% growth over 12 months — be careful with optimistic assumptions. The simulation caps at 120 months (10 years). If cash never reaches zero in that window, the runway is shown as 120 months and the company is flagged default alive. All figures accumulate as floating-point and are rounded only in output.
Frequently asked questions
What is the difference between gross burn and net burn?+
Gross burn is the total cash you spend in a month — salaries, rent, software, marketing — before any revenue arrives. Net burn is what remains after subtracting revenue: it is the rate at which your cash balance actually shrinks. Investors and founders often quote net burn for operational planning and gross burn when discussing the cost structure of the business. Both numbers matter: a high gross burn with strong revenue can have the same net burn as a lean startup with no customers.
What does 'default alive' mean?+
Paul Graham introduced the term in a 2015 essay. A startup is default alive if, assuming roughly current trends, it will reach profitability before running out of money. It is default dead if it will exhaust its cash before revenue covers costs — and therefore must raise more capital to survive. This calculator operationalises the test: if your revenue growth trajectory leads to a month where revenue ≥ expenses before the bank account hits zero, you are default alive. Note that this is a projection, not a promise; actual outcomes depend on execution and market conditions.
How accurate is the revenue growth model?+
The model applies a fixed month-over-month compounding growth rate to both revenue and expenses. This is a simplification: real growth is lumpy, not smooth. Use conservative growth rates (the rate you have actually achieved over the last three months, not your plan) and run multiple scenarios. A 3% monthly revenue growth rate feels modest but compounds to 43% annually; a 10% monthly rate implies 214% annual growth, which is rare beyond the earliest stages. This calculator is a planning tool, not a forecast — its value is in comparing scenarios, not producing a single definitive number. It is not financial advice.