How to use the startup runway calculator
- Enter cash in the bank.
- Add monthly revenue and its expected growth rate.
- Add monthly expenses and their growth.
- Read your runway and break-even month.
The formula
Cashₘ = Cashₘ₋₁ + Revenueₘ − Expensesₘ, with Revenue and Expenses growing at their monthly rates
The simple runway figure (cash ÷ net burn) assumes nothing changes; the modeled figure reflects your growth assumptions.
Worked example
With 250,000 in cash, 12,000 revenue growing 8% a month and 38,000 expenses growing 2%, the model shows how many months you have and whether break-even arrives before the cash runs out.
Tips from the numbers
- Start fundraising with at least 6–9 months of runway left.
- Model a 'bad case' with half the growth rate.
- Default alive vs. default dead: know which one you are today.
Watch: learn the concept
Frequently asked questions
What is burn rate?
Gross burn is total monthly spending; net burn is spending minus revenue.
How much runway is healthy?
Many founders aim for 18–24 months after a raise.
Is this financial advice?
No — it's a modeling tool. Combine it with your actual accounting data.
Want a second opinion? Our free review connects you with a vetted professional for your situation. Get matched →