Startup Cash Runway Calculator
See how many months your cash will last at your current burn rate, plus your estimated zero-cash date.
This calculator runs entirely in your browser. Nothing you type is uploaded or stored.
How to use this tool
This startup runway calculator turns your cash and burn into a simple timeframe: how many months you can operate before the balance reaches zero. Fill in three fields and press Calculate runway.
- Enter your cash on hand — the total money in your bank and easily accessible accounts right now.
- Enter your total monthly expenses — payroll, rent, software, marketing, and everything else you spend each month.
- Enter your monthly revenue — the cash that actually comes in each month. If you have none yet, leave it as 0.
- Press Calculate runway. The tool shows your net monthly burn rate, the months of runway you have left, and an estimated zero-cash date offset.
Use the Copy result button to paste the numbers into an investor update, a board deck, or your own cash flow notes.
The formula: how cash runway is calculated
Months of runway = Cash on hand ÷ Net monthly burn
Zero-cash date ≈ today + (Months of runway) months
Runway is your survival timeframe. The key number is net burn — how much cash leaves the business after you subtract what comes in. If your revenue equals or exceeds your expenses, your net burn is zero or negative, which means you are cash-flow positive and have effectively unlimited runway at the current rate. This is the heart of small business cash flow survival: knowing the monthly burn rate timeframe before the money runs out, not after.
A real example
Imagine a seed-stage startup with $250,000 in the bank. It spends $60,000 a month on salaries, rent, and tools, and brings in $18,000 a month in revenue.
Net monthly burn = $60,000 − $18,000 = $42,000. Months of runway = $250,000 ÷ $42,000 = about 5.95 months. Starting from today, that points to a zero-cash date roughly six months out. With that clarity, the founders know they should either close a raise, cut burn, or grow revenue well before then — this is the business capital lifecycle in plain numbers.
Common questions
What is a healthy amount of startup runway?
Many investors suggest keeping at least 12 to 18 months of runway, since fundraising and revenue growth almost always take longer than planned. Below six months is usually treated as a warning zone that calls for cutting burn or raising capital quickly.
What is the difference between gross burn and net burn?
Gross burn is your total monthly expenses with no offset. Net burn subtracts the revenue you collect each month. This calculator uses net burn because it reflects how fast your actual cash balance is shrinking, which is what determines real runway.
What happens if my revenue is higher than my expenses?
Then your net burn is zero or negative, meaning you are cash-flow positive at the current rate. The tool reports that you are not burning cash, so there is no zero-cash date to project from these inputs.
How accurate is the zero-cash date estimate?
It is a straight-line projection that assumes your burn and revenue stay flat. Real businesses see costs and income change month to month, so treat the date as a planning guide and revisit it whenever your numbers shift.
Is this financial advice?
No. This monthly burn rate calculator is for educational planning only and gives simplified estimates, not professional financial, accounting, or investment advice. Confirm decisions with a qualified advisor before acting on them.