Runway is one of the most important metrics for startups and growing SaaS companies. When you are using cash to fund product development, hiring, marketing, and infrastructure, you are actively converting cash into growth. That means visibility into cash is not optional; it determines how long you can continue operating at your current pace.
In this article, you will learn how to calculate runway, understand what truly drives burn, and manage both as active operating metrics (rather than static numbers).
Cash runway answers a core question for your business:
“How long can we operate at your current burn before cash hits zero?”
That number influences hiring plans, fundraising timing, and risk tolerance. Without clarity into your runway, growth decisions are disconnected from the reality of your finances.
In our latest episode of Founder Files, I sit down with Carter Looney to talk about why profit does not equal cash and what that really means for runway.
What is Cash Runway?
“Cash runway” (runway) shows the number of months a company can remain in business before reaching zero dollars in the bank. It is calculated like this:
Runway = current cash balance ÷ burn rate (monthly)
If you have $1,000,000 in the bank and you burn $100,000 per month, you have 10 months of runway. That means, assuming revenue and expenses stay consistent and no new capital is raised, you have 10 months before your cash goes to zero.
Runway is a forward-looking estimate based on current conditions.
For growing SaaS companies, runway matters because investors and board members evaluate it when assessing risk. It also determines when fundraising conversations must begin. Raising capital used to take 9 to 18 months. Now the cycles are increasing and being on schedule has become more important. If you wait until you have 3 or 6 months left, you have compressed your negotiating power.
Definition Bank:
- Cash balance: The actual money available in your bank accounts.
- Runway: The number of months a company can operate before cash reaches zero.
- Burn rate: The amount of cash a company loses each month.
Burn Rate: The Number That Drives Runway
To determine runway, you must also determine burn rate. Burn rate measures how much cash your business is losing per month.
The most relevant metric for growing companies is net burn:
Net burn = monthly cash inflows − monthly cash outflows
If the result is negative, you are burning cash.
Example:
- Monthly cash inflows: $200,000
- Monthly cash outflows: $300,000
- Net burn: ($100,000)
This means your cash balance declines by $100,000 every month.
There is also gross burn, which refers to total monthly cash expenses before considering revenue. Net burn is more useful in this case because it reflects the actual decline in cash after cash inflows are accounted for.
Some founders calculate burn by comparing starting and ending bank balances. That can work too, but it can be misleading if the company raised capital, took on debt, or received a one-time inflow. Those financing events distort operational burn.
Burn is not a theoretical number; it is the gap between what you collect and what you spend. That gap determines how quickly your runway shortens.
When we work with SaaS companies at Cypher, we often find that burn is overstated or understated because invoice timing, collections, or deferred revenue are not modeled correctly. Cleaning that up frequently changes how much real runway a company actually has.
Definition Bank:
- Cash inflows: Money received from customers or other sources.
- Cash outflows: Money paid for payroll, vendors, software, rent, and other expenses.
- Net burn: The monthly decrease in cash after inflows and outflows are accounted for.
- Gross burn: Total monthly cash expenses.
If you’re not fully confident in how your burn is calculated, Cypher helps founders and CEOs align cash inflows, outflows, and forecasting so runway reflects real operating conditions.
What Is a Healthy Runway?
There is no single “correct” number, but practical benchmarks exist.
It used to be that 6-9 months of runway was considered prudent. Today, 9 months is no longer a comfort buffer; it’s often just the fundraising lead time.
With venture markets tighter and diligence cycles longer, growing companies should operate with 18 to 24 months of runway as a baseline. That window gives management enough time to hit meaningful milestones, product, revenue, or profitability, before returning to market from a position of strength.
Recent data indicates that more than half of VCs are now encouraging portfolio companies to maintain at least 18 to 24 months of runway ahead of their next raise. In more volatile environments, it is advisable to be even more conservative with a 24 to 36-month runway to protect against timing risk and valuation pressure.
Runway gives you flexibility and allows you to:
- Test growth initiatives
- Adjust pricing or strategy
- Navigate churn
- Raise capital from a position of strength
A shorter runway limits your options and forces reactive decisions.
The Mental Model Founders May Be Getting Wrong
Bookings are contract value, not revenue, profit, or cash. In SaaS, bookings represent the total value of signed contracts. However, bookings do not determine how much cash you collect in a given month.
Cash inflows depend on:
- Invoices: Formal requests for payment sent to customers.
- Net terms: The number of days customers have to pay an invoice (e.g., Net 30 means payment is due in 30 days).
- Collection timing: When customers actually transfer funds.
To predict runway accurately, you must understand when invoices convert to cash. Modeling revenue without modeling invoice timing leads to incorrect burn figures.
Revenue growth does not guarantee liquidity. A company can grow quickly while cash collection lags behind expenses. That timing gap directly impacts the calculation of cash metrics.
This is exactly what we corrected in our work with Galaxy Digital, where tightening billing operations and improving collections reduced days sales outstanding and strengthened cash conversion.
Definition Bank:
- Bookings: Total contract value signed in a period.
- Invoice: A bill issued to a customer requesting payment.
- Net terms: Payment deadlines assigned to invoices (Net 15, Net 30, Net 60, etc.).
- Liquidity: The ability to meet short-term financial obligations using available cash.
Before making hiring or fundraising decisions, many founders and CEOs turn to Cypher to ensure bookings, collections, and burn are aligned with real cash visibility.
Why Runway Changes
Runway is dynamic and changes whenever burn changes.
Common drivers include:
- Churn: The rate at which customers cancel subscriptions.
- Accelerated hiring.
- Increased software and infrastructure spending.
- Unplanned tax payments.
In subscription businesses, churn has a compounding effect. Even small increases in churn reduce recurring revenue, which increases net burn and shortens runway.
Tax obligations are another overlooked factor. Companies that do not plan for quarterly tax payments may experience sudden cash reductions.
Runway requires ongoing monitoring because operating conditions evolve.
In our work with high-growth SaaS companies, we monitor runway monthly alongside churn, hiring plans, and margin performance so that leadership teams can adjust before pressure builds rather than after cash tightens.
Definition Bank:
- Churn rate: The percentage of customers who cancel during a given period.
- Recurring revenue: Revenue generated from ongoing subscriptions.
- Operating expenses (OPEX): Ongoing costs required to run the business.
Forecasting Makes Runway Actionable
Once you’ve calculated your current runway, the next step is a cash flow forecast.
A cash flow forecast projects expected inflows and outflows over future months. It helps you anticipate changes in burn, shifts in revenue timing, upcoming expense increases, and future cash gaps before they occur.
Tracking actual results versus forecasted numbers allows you to measure forecast variance. Forecast variance highlights whether spending, collections, or revenue assumptions are deviating from plan.
Runway without forecasting is static. It tells you where you stand today, but it doesn’t help you prepare for what’s coming.
Runway combined with forecasting becomes proactive management. It lets you make decisions with visibility into how they will impact cash before the impact hits your bank account.
Several of our clients, including Travelsist, have used structured financial modeling and forecasting to strengthen fundraising readiness, refine hiring plans, and enter investor conversations with defensible projections and clear economic assumptions.
If you want to understand how forecasting supports runway decisions, read our full breakdown here: Financial Forecasts for High-Growth Companies: How to Use Them (Not Just Build Them).
Definition Bank:
- Cash flow forecast: A projection of future cash inflows and outflows.
- Forecast variance: The difference between projected and actual financial results.
Hiring Through the Lens of Runway
Hiring decisions directly affect burn. When a founder plans to hire multiple team members in a quarter, the key questions are:
- Was this modeled in the forecast?
- Does current cash support the increased burn?
- How does this change runway?
Each hire increases fixed monthly expenses. If revenue growth does not offset that increase, net burn rises and runway shortens.
Hiring should be connected to forecasted revenue, margin assumptions, and runway targets. Growth initiatives must align with cash capacity.
Definition Bank:
- Fixed expenses: Costs that remain consistent regardless of revenue fluctuations.
- Margin: The percentage of revenue remaining after covering direct and operating costs.
When Runway Is Tight
If you have less than six months of runway and no term sheet in sight, here are the first moves to make.
First, reduce discretionary expenses.
Second, evaluate your pipeline (confirmed revenue opportunities that are likely to convert into cash).
Third, consider structured ways to extend time, such as SBA loans, invoice factoring, or revenue-based debt.
Each of these tools buys time, and they must be integrated into a revised forecast to ensure repayment does not create a future cash strain.
Definition Bank:
- Pipeline: Potential revenue opportunities expected to close.
- SBA loan: A government-backed small business loan that provides capital with structured repayment terms.
- Invoice factoring: Selling outstanding invoices to receive cash immediately.
- Revenue-based debt: Financing repaid as a percentage of revenue over time.
Why This Matters for Growth-Stage Companies
Runway influences hiring plans, product investment, fundraising timing, and board discussions. Growth-stage companies often experience cash pressure because expansion outpaces cash visibility.
Runway discipline reduces risk and supports better decision-making while strengthening investor confidence.
At Cypher, we focus on building real cash visibility through aligning burn, forecasts, hiring plans, and fundraising readiness. That includes improving invoice timing clarity, monitoring forecast variance, and ensuring runway calculations reflect operational reality.
Runway is not a one-time calculation. It’s a metric you manage consistently as the business grows that shapes decision-making.
Tech-Enabled Accounting & Finance. Built for Growth.
FAQ
What is cash runway?
Cash runway is the number of months a company can operate before cash reaches zero.
How do you calculate runway?
Runway equals current cash balance divided by monthly net burn.
What is net burn?
Net burn is the monthly decrease in cash after subtracting cash outflows from cash inflows.
How much runway should a SaaS company have?
A practical target today is 18–24 months of runway, especially in tighter capital markets. In more volatile environments, 24–36 months provides additional flexibility and negotiating strength during fundraising.
Why doesn’t revenue growth guarantee strong runway?
Revenue does not automatically convert to immediate cash. Invoice timing and payment terms affect liquidity.
How often should runway be reviewed?
At least monthly, and more frequently during high-growth or high-burn periods.
