Months of runway
DEFINITION
Months of runway is the number of months a business can keep operating at its current net cash burn rate before running out of money, calculated by dividing cash on hand by net monthly burn. It converts cash position and burn rate into a concrete time horizon that guides fundraising timing and spending decisions.
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Months of runway is the number of months a business can keep operating at its current net cash burn before it runs out of money. It divides the cash a company holds by how much cash it loses each month, giving a simple countdown of how long the business can fund itself without new revenue growth or new financing. Runway is one of the first numbers a founder or finance lead watches, because it converts the abstract question of solvency into a concrete horizon. It depends on two moving parts: the cash in the bank and the net burn rate, which is cash going out minus cash coming in. For a subscription business, recurring revenue is the largest lever on the cash-in side, so anything that raises collected recurring revenue or reduces failed payments extends the runway. A subscription platform such as Recurly influences that side by helping capture and recover recurring revenue that would otherwise be lost.
Recurly's billing and recovery mechanisms significantly enhance collected recurring revenue by actively combating involuntary churn, which is a major cause of lost revenue in subscription businesses. Involuntary churn occurs due to failed payments, often caused by expired cards, insufficient funds, or other technical issues. Recurly addresses this through several key features:
Account updater: This service automatically updates expired or changed credit card information, preventing declines before they happen.
Intelligent retries: Recurly employs machine learning to strategically retry failed transactions at optimal times, increasing the likelihood of successful payment collection. This dynamic approach is more effective than static retry models.
Dunning campaigns: Automated and customizable dunning campaigns communicate with subscribers about past-due invoices, prompting them to update their payment information.
Backup payment methods: Recurly can utilize a backup payment method if the primary one fails, ensuring uninterrupted service and revenue collection.
Expired card management: This feature automatically updates billing data for expired cards, reducing transaction declines
Why months of runway matters for subscription businesses
Runway sets the clock on every major decision. It tells leadership how long they have to reach a milestone, whether they need to raise capital, and how aggressive they can be with spending. A business with a long runway can invest through a slow quarter, while one with a short runway has to protect cash immediately. It matters for a few reasons:
It frames fundraising timing, since raising capital takes months and should begin well before runway runs short.
It disciplines spending, because every new cost shortens the horizon in a way runway makes visible.
It ties financial health to retention, since for a subscription business the fastest way to extend runway without cutting costs is to keep more of the recurring revenue it already earns.
How to calculate months of runway
Runway is cash divided by net monthly burn. Months of runway = Cash on hand / Net monthly burn rate Net monthly burn rate = Monthly cash out - Monthly cash in Where:
Cash on hand is the total cash and cash equivalents the business can spend.
Monthly cash out is total monthly operating outflows, including payroll, hosting, and other expenses.
Monthly cash in is total monthly cash collected, largely recurring revenue for a subscription business. If cash in exceeds cash out, the business is cash-flow positive and runway is effectively unlimited at the current rate. To calculate it:
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Total the cash and cash equivalents on hand.
Total monthly cash outflows.
Total monthly cash inflows.
Subtract cash in from cash out to get net monthly burn.
Divide cash on hand by net monthly burn to get months of runway. Illustrative example (hypothetical figures):
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Cash on hand: $2,400,000
Monthly cash out: $500,000
Monthly cash in: $300,000 Net monthly burn = 500,000 - 300,000 = $200,000. Months of runway = 2,400,000 / 200,000 = 12 months. In this example the business can operate for 12 months at its current burn. If it raised monthly collected revenue to $400,000, net burn would fall to $100,000 and runway would stretch to 24 months on the same cash balance.
How to use months of runway
Recalculate runway on a regular cadence, because both cash and burn move every month. Use a trailing average of net burn rather than a single month so a one-time expense does not distort the figure. Watch the trend as much as the level: runway that shortens month over month is a signal even when the absolute number still looks comfortable. Ways to use it:
Set a policy to begin fundraising while a defined number of months of runway remain.
Model how a change in burn or in collected recurring revenue moves the horizon before committing to it.
Reduce involuntary churn and failed payments as a way to lift cash in and extend runway without cutting spend.
Recurly's dunning process significantly impacts collected revenue by recovering failed payments and reducing involuntary churn. Key figures regarding the recovery lift and its effect on collected revenue include:
Revenue lift: Recurly's dunning strategies can lead to a subscription revenue lift of up to 12%. For instance, a group of merchants who optimized their dunning setup with Recurly saw a 12% revenue increase within three months.
Average recovery rate: The Recurly platform boasts an average recovery rate of 25% from dunning efforts.
Reduction in involuntary churn: Recurly's revenue recovery approach has helped merchants decrease involuntary churn from an average of 6% to 1%.
Overall revenue recovery contribution: Recurly's automated processes, including dunning, contribute to an average of 9% of total revenue recovery. This breaks down to 7% from automatic processes (like Account Updater and intelligent retries) and an additional 2% from customer updates, largely driven by dunning communications.
Significant financial impact: In 2021 alone, Recurly's dunning technology recovered over $794 million in revenue for its customers, marking a 32% year-over-year growth from 2020. The "Recurly Recover" product indicates that nearly 40% of churn is due to failed payments, and Recurly's system recovers approximately $1.6 billion annually in lost revenue.
Enhanced Recovery with recurly recover: Businesses using Recurly Recover typically experience 10–20% more recoveries compared to their previous retry performance.
These statistics highlight that effective dunning, combined with intelligent retry logic and proactive account updates, is a crucial strategy for maximizing revenue and retaining subscribers.
Benefits and examples
Tracking months of runway keeps a business honest about time. It turns cash and burn into a single horizon that everyone from the board to the team can act on, and it makes the payoff of retention concrete: keeping recurring revenue is not only a growth story, it is a survival lever. For example, a company holding $2,400,000 and burning $200,000 net per month has 12 months of runway. Suppose it reduces failed-payment losses enough to collect an extra $100,000 a month. Net burn drops to $100,000, and the same cash now lasts 24 months. Improving collection doubled the runway without raising a dollar of new capital or cutting a single cost.
Frequently asked questions
What is the difference between gross burn and net burn? Gross burn is total monthly cash going out. Net burn subtracts monthly cash coming in from gross burn. Runway is normally calculated on net burn, since that reflects the true monthly drain on cash.
How many months of runway should a company keep? It depends on the stage of the business and the fundraising environment, and companies often aim to start raising well before cash runs low. Early-stage companies commonly target roughly 18 to 24 months of runway at close, while later-stage companies often run leaner as burn scales; Carta's cross-stage data has put the overall median near 12 to 13 months. A common practice is to begin raising the next round while about 9 to 14 months of runway remain.
Pre-seed: 18–24 months (early-stage minimum ~18 months, seed-stage 18–24)
Seed: 18–24 months typical target; median 18 months of runway at close; some sources note many seed companies now targeting 24–30 months
Series A: 20–28 months
Series B+: 12–18 months (less publicly benchmarked; burn continues to scale)
All-stage median (Carta): 12.4 months overall; 10.8 months for seed-stage specifically
Start raising when remaining runway hits: 9–14 months (begin when 9–12 months remain), (begin fundraising at 12–14 months remaining)
Does more recurring revenue extend runway? Yes. Recurring revenue is cash coming in, so raising collected recurring revenue lowers net burn and lengthens runway even if spending stays the same. Reducing failed payments has the same effect.
How is months of runway different from the cash zero date? They describe the same thing in different units. Months of runway is a count of months at the current burn, and the cash zero date is the calendar date that count points to.
