BUSINESS
Runway Calculator - How Long Will Your Cash Last
By Worldtickers ·
Calculate how many months your cash reserves will last based on your burn rate and revenue trajectory.
This runway tool focuses on calculating how many months your cash reserves will last based on your burn rate and revenue trajectory. Use it to turn operating metrics into practical business insight by entering costs, revenue, customers, margins, or growth assumptions and reviewing the numbers behind better decisions.
Calculator
Runway Calculator
Project how many months your cash will last.
Net Burn
$0.00
Cash Runway (months)
N/A
Projected Exhaustion Date
N/A
What Is Runway
Runway is the measure of how long a startup or business can continue operating before it exhausts its cash reserves. Expressed in months, runway answers the most fundamental question every founder faces: how much time do we have? It is calculated by dividing the current cash balance by the monthly net burn rate — the amount of cash the company loses each month after accounting for revenue. A company with $600,000 in the bank and a $60,000 monthly net burn has 10 months of runway.
Runway is not just a number — it is a strategic constraint that shapes every decision a startup makes. With 18 months of runway, a founder can invest in long-term product development, experiment with marketing channels, and hire carefully. With 4 months of runway, the same founder is forced into survival mode — cutting costs, rushing to close deals, and raising emergency funding at unfavorable terms. Maintaining adequate runway is not just about survival; it is about preserving optionality and negotiating leverage.
For investors, runway is a key risk indicator. A startup with 充足的 runway can take measured risks, iterate on product-market fit, and grow sustainably. A startup running out of cash makes desperate decisions that often destroy value. Investors typically want to see at least 12–18 months of runway after their investment, giving the company enough time to hit the milestones needed to raise the next round or reach profitability.
The relationship between runway and burn rate is dynamic. As revenue grows, net burn decreases and runway extends — assuming expenses remain constant. Conversely, if expenses grow faster than revenue, burn rate increases and runway shrinks. This is why the most sophisticated runway calculations incorporate revenue growth projections, not just current-month snapshots. The calculator below supports both approaches: a simple static calculation and a growth-adjusted projection.
How to Use This Calculator
Enter your current cash balance, monthly expenses, monthly revenue, and optionally your monthly revenue growth rate. The calculator computes your runway in months using both the static method (constant burn) and the growth-adjusted method (declining burn as revenue increases).
Cash Balance
Enter your total available cash — bank accounts, money market funds, and short-term investments that can be quickly liquidated. Do not include lines of credit, venture debt facilities, or illiquid assets. Cash balance is the numerator in the runway calculation, so accuracy here is essential.
Monthly Expenses and Revenue
Enter your total monthly cash expenses and total monthly cash revenue. Use the most recent month or a 3-month average if your numbers fluctuate. Expenses should include all cash outflows (salaries, rent, infrastructure, marketing, etc.). Revenue should be cash received, not invoiced amounts.
Revenue Growth Rate
If your revenue is growing, enter the monthly growth rate as a percentage. The calculator will project future months assuming revenue grows at this rate while expenses remain constant. This gives a more accurate runway estimate for growing businesses. Leave this at 0% for a conservative static estimate.
Formula
Simple runway: Runway (months) = Cash Balance / Net Burn, where Net Burn = Monthly Expenses − Monthly Revenue.
Growth-adjusted runway: project each future month's revenue as Revenue × (1 + Growth Rate)^Month, compute net burn for each month, subtract from remaining cash, and count months until cash reaches zero.
Zero cash date: ZCD = Today + Runway (months)
Examples
Example 1: Static Runway (No Revenue Growth)
Cash: $500,000. Monthly expenses: $80,000. Monthly revenue: $20,000. Net burn: $60,000. Runway: $500,000 / $60,000 = 8.3 months. Zero cash date: approximately 8 months from today. At this burn rate, the startup needs to either become profitable or raise funding within 6 months to allow time for a fundraising process.
Example 2: Growth-Adjusted Runway
Cash: $500,000. Monthly expenses: $80,000. Monthly revenue: $20,000. Revenue growth: 10% per month. Month 1 net burn: $60,000. Month 2: revenue = $22,000, net burn = $58,000. Month 3: revenue = $24,200, net burn = $55,800. The declining burn rate extends runway. The growth-adjusted calculation shows approximately 11.5 months of runway — 3+ months longer than the static estimate. This demonstrates why revenue growth is the most powerful lever for extending runway.
Example 3: Pre-Revenue Startup
Cash: $1,200,000. Monthly expenses: $100,000. Revenue: $0. Runway: $1,200,000 / $100,000 = 12 months. This startup has a full year to build its product, achieve product-market fit, and either generate revenue or raise its next round. If the team can reduce expenses to $80,000 by cutting non-essential costs, runway extends to 15 months — a significant improvement from a relatively small adjustment.
Tips
Maintain 12–18 Months of Runway
The general rule is to always have at least 12–18 months of runway. This gives you enough time to fundraise comfortably (3–6 months for the process), hit meaningful milestones, and avoid negotiating from a position of desperation. If your runway drops below 9 months, immediately begin cost-cutting measures or fundraising conversations.
Track Runway Monthly
Update your runway calculation every month as part of your financial review. Plot it over time to see the trend — is runway increasing (good) or decreasing (warning sign)? A decreasing runway means burn is outpacing revenue growth, which requires immediate attention before it becomes a crisis.
Model Multiple Scenarios
Don't rely on a single runway number. Model best case (revenue grows faster than expected), base case (revenue grows as expected), and worst case (revenue stalls or declines). Having visibility into all three scenarios helps you plan contingencies and make better decisions about hiring, spending, and fundraising timing.
Factor in Upcoming Large Expenses
A simple runway calculation assumes expenses remain constant, but reality often includes large one-time expenses — annual insurance premiums, equipment purchases, legal filings, or tax payments. Adjust your runway calculation to account for these known upcoming expenses to avoid surprises. When in doubt, subtract a buffer from your cash balance to create a safety margin.
FAQ
What is startup runway?
Runway is the amount of time — measured in months — that a startup can continue operating before it runs out of cash. It is calculated by dividing the current cash balance by the monthly net burn rate (expenses minus revenue). Runway is one of the most important metrics for founders and investors because it determines how long the company has to reach profitability, secure additional funding, or pivot the business model.
How much runway should a startup have?
Most investors recommend maintaining at least 12–18 months of runway at all times. This provides enough time to hit milestones, fundraise strategically, and make adjustments without desperation. Having less than 6 months of runway is dangerous — it limits your options and forces you to raise money from a position of weakness. Having more than 24 months of runway can mean you are not investing aggressively enough in growth.
What is the difference between runway and burn rate?
Burn rate is the speed at which you are spending cash (dollars per month). Runway is how long your remaining cash will last at that speed (months). They are related but serve different purposes: burn rate tells you how fast you are consuming resources, while runway tells you when those resources will be exhausted. Both metrics should be tracked together — improving burn rate extends runway, and monitoring runway puts burn rate in context.
How does revenue growth affect runway?
Revenue growth directly extends runway by reducing net burn. If your expenses stay flat but your revenue increases, your net burn decreases and your runway extends. For example, a company with $100,000 in expenses and $20,000 in revenue (net burn = $80,000) has shorter runway than the same company with $60,000 in revenue (net burn = $40,000). This is why investors focus on the burn multiple — the ratio of burn to revenue growth — to assess capital efficiency.
When should I start fundraising?
Start fundraising when you have at least 6–9 months of runway remaining. Fundraising typically takes 3–6 months from first meeting to closing. If you wait until you have only 3 months of runway, investors will sense urgency and negotiate harder terms. Starting early also gives you the luxury of walking away from bad deals. The best fundraising happens when you are not desperate — when you can demonstrate strong metrics and tell investors you are raising for growth, not survival.
Can runway be extended without raising money?
Yes. You can extend runway by reducing expenses (cutting burn rate), increasing revenue (growing faster), or both. Cost reduction is the fastest lever — lay off non-essential staff, renegotiate contracts, eliminate waste, and focus spending on the highest-ROI activities. Revenue growth takes longer but is more sustainable. Some companies extend runway by collecting receivables faster, extending payables, or using revenue-based financing. The calculator shows how different expense and revenue scenarios affect your runway.
What is zero cash date?
Zero cash date (or ZCD) is the specific date when your cash balance will reach zero, assuming the current burn rate continues. It is the concrete version of runway — instead of saying 'we have 10 months of runway,' you say 'we will run out of cash on March 15, 2027.' ZCD is more actionable because it creates a specific deadline for fundraising, profitability, or other actions. Many board decks include ZCD alongside runway for this reason.
How do I calculate runway with growing revenue?
Simple runway calculation (cash / net burn) assumes a constant burn rate, but if revenue is growing, net burn is shrinking month over month. To calculate runway more accurately, model your revenue growth rate month by month, subtract projected expenses each month, and count how many months until cash hits zero. The calculator provides both the simple estimate and a growth-adjusted estimate when you enter your monthly revenue growth rate.