Startup Runway Calculator
Calculate your startup's cash runway, monthly net burn, and projected cash-out date. Model revenue and expense growth to see when you reach break-even or need to raise.
Cash in the bank available to fund operations
Month-over-month growth (leave blank for flat)
How fast costs rise as you scale
An incoming round, grant, or loan added to your cash
Runway is the single number that keeps founders awake at night, and for good reason. It tells you how many months your company can keep the lights on before the bank balance hits zero. Borrowed from aviation, the metaphor is apt: a plane needs enough runway to reach takeoff speed, and a startup needs enough cash to reach the point where it can sustain itself or raise its next round. Run out of runway before either happens, and the journey ends regardless of how promising the product was.
For an early-stage company, runway is more honest than almost any other metric. Revenue can be lumpy, vanity metrics can flatter a pitch deck, and projections can be optimistic, but the cash balance is a fact. Knowing your runway down to the month changes how you hire, how aggressively you spend on growth, and when you start fundraising. It turns a vague sense of urgency into a concrete deadline you can plan around.
This calculator estimates runway by projecting your cash forward month by month. Instead of freezing today's revenue and expenses in place, it lets you apply growth rates to both, so the result reflects how your business actually evolves. The output includes your monthly net burn, the number of months of runway remaining, a projected cash-out date, and whether you reach break-even before the money runs out.
The textbook formula is simple. Take your cash on hand and divide it by your monthly net burn:
Runway (months) = Cash on Hand ÷ Monthly Net Burn
If you have $500,000 in the bank and you lose $50,000 a month after accounting for revenue, that's ten months of runway. The trouble with this version is that it assumes your burn never changes. In reality, revenue tends to grow, expenses creep upward as you hire, and a single static number can be wildly off for a company on a steep trajectory.
That is why this calculator runs a month-by-month simulation. It starts with your current cash, then for each future month it grows revenue and expenses by the rates you provide, subtracts the new expenses from the new revenue, and updates the cash balance. The runway is the month in which that balance first reaches zero. If your revenue grows faster than your costs, the model can show that you never run out of cash at all, something the simple division can never capture.
Burn rate is how fast you spend cash, but there are two flavors and mixing them up leads to bad decisions. Gross burn is the total amount you spend each month: salaries, rent, software, cloud bills, marketing, and everything else combined. Net burn subtracts the revenue you collect, showing the cash you actually lose.
$80,000 spent every month on the full cost base, regardless of how much revenue comes in.
$80,000 expenses minus $30,000 revenue equals a $50,000 net burn, the figure that actually drains your runway.
Runway is driven by net burn, which is why revenue is such a powerful lever. Every dollar of recurring revenue you add reduces your net burn dollar for dollar and stretches your runway. When net burn turns negative, you are cash-flow positive and your runway becomes effectively unlimited on that trajectory.
The most useful thing you can do with a runway model is run scenarios. A static calculation answers one question; a dynamic model answers dozens. By adjusting revenue growth, expense growth, and a one-time funding injection, you can stress-test your plan against optimistic, realistic, and pessimistic futures before committing real money.
Suppose your revenue grows 8% per month while expenses grow only 3%. Each month your net burn shrinks, and the model may show you crossing into profitability with cash to spare. Now flip it: hold revenue flat while expenses climb 5% a month as you add headcount, and the same starting cash buys you far fewer months. Seeing both outcomes side by side is what separates a plan from a hope.
Runway and break-even are two sides of the same coin. Runway tells you how long you can survive; break-even tells you the month your revenue finally covers your expenses so you stop burning cash. The critical question for any founder is whether break-even arrives before the runway ends. If it does, the business can become self-sustaining without another dollar of outside capital. If it does not, you need to raise, cut, or grow faster.
This calculator flags exactly that. When your projected break-even month falls inside your runway, it confirms you are on a sustainable path. When break-even sits beyond the cash-out date, or never arrives in the projection, it is an early warning that your current trajectory does not add up. For a deeper unit-level view of where revenue overtakes cost, pair this with the break-even analysis calculator, which works out the exact sales volume you need to cover fixed and variable costs.
There is no universal answer, but seasoned operators and investors tend to converge on similar guardrails. Most advise keeping 12 to 18 months of runway after a raise, and starting the next fundraise when roughly 6 to 9 months remain. The logic is straightforward: fundraising routinely takes three to six months, and you want to negotiate from strength rather than desperation.
| Runway Remaining | What It Usually Signals |
|---|---|
| 18+ months | Healthy; focus on growth and milestones |
| 9–12 months | Begin preparing the next raise |
| 6–9 months | Actively fundraise or tighten spending |
| Under 6 months | Danger zone; cut burn and move fast |
These are guidelines, not gospel. A profitable or near-profitable company can operate comfortably on far less runway than a deeply unprofitable one chasing growth. The right buffer depends on how predictable your revenue is and how quickly you could cut costs if you had to.
When the math gets tight, you have three levers: raise more cash, grow revenue, or reduce expenses. Each behaves differently. Cutting costs lowers net burn immediately, so it is the fastest way to buy time. Growing revenue compounds, so a small bump in growth rate today can add many months down the line. Raising capital resets the clock entirely but takes time and dilutes ownership.
The most frequent error is treating runway as a fixed snapshot. Founders calculate it once after closing a round and never revisit it, even as hiring accelerates burn. Runway is a living number that should be recalculated every month against actual results, not a figure you write down once and forget.
A second mistake is being optimistic about revenue and conservative about expenses, when reality is usually the reverse. New hires ramp slower than planned, deals slip, and one-off costs appear from nowhere. Build your base case on what has actually happened, not what you hope will happen, and keep a downside scenario handy. Finally, do not forget about one-time costs and the timing of cash, not just accounting revenue. A signed contract that pays in 90 days does nothing for the payroll due next week. Always plan around when cash actually lands in the bank.
Runway is the number of months your startup can keep operating before it runs out of cash, assuming your current spending and income patterns continue. The simplest version divides your cash balance by your monthly net burn (expenses minus revenue). This calculator goes further by projecting each month forward and applying your revenue and expense growth rates, so the runway reflects how your numbers actually change over time rather than freezing them at today's snapshot.
Gross burn is the total cash you spend each month on salaries, rent, software, marketing, and everything else. Net burn subtracts the revenue you bring in, so it shows how much cash you actually lose each month. A company with $80,000 in expenses and $30,000 in revenue has an $80,000 gross burn but a $50,000 net burn. Runway is driven by net burn, which is why growing revenue extends your runway even if your spending stays flat.
A common rule of thumb is to keep 12 to 18 months of runway, and to start raising your next round when you have roughly 6 to 9 months left. Fundraising takes time, and investors prefer to back companies negotiating from a position of strength rather than desperation. If your runway dips below six months without a clear path to revenue or a funding commitment, it's usually a signal to cut burn, accelerate sales, or open conversations with investors immediately.
A static runway calculation assumes your revenue and costs never change, which is rarely true for a startup. If revenue grows faster than expenses, your net burn shrinks every month and your real runway is longer than a simple snapshot suggests, sometimes reaching profitability before the cash runs out. If expenses grow faster than revenue, your runway is shorter than the naive estimate. Modeling both growth rates gives a far more realistic cash-out date.
Break-even is the month your monthly revenue first equals or exceeds your monthly expenses, meaning you stop burning cash. If the calculator shows you reach break-even before your runway ends, your business can become self-sustaining on its current trajectory. If break-even never arrives within the projection, you'll need outside funding or a change in your revenue and cost trajectory to survive beyond the cash-out date.
There are three main levers: raise more cash, increase revenue, or reduce expenses. Cutting non-essential spending and lowering net burn has an immediate effect, while raising prices or accelerating sales growth compounds over time. Use this calculator to test scenarios, for example trimming monthly expenses by 15% or lifting revenue growth from 5% to 10%, and watch how the runway and cash-out date shift before you commit to a plan.
Yes. Add any committed cash injection such as a new investment, grant, or loan to your starting cash so the runway reflects the money you'll actually have. For large one-off costs like a big equipment purchase or a legal settlement, it's safest to subtract them from your starting cash too, since they reduce the buffer available to cover ongoing monthly burn. Recurring costs belong in your monthly expenses instead.
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