Runway
Runway is the number of months a company can continue operating at its current burn rate before running out of cash. It represents the time available to reach profitability or secure additional funding.
Also known as: cash runway, months of runway, financial runway
Formula
Cash Balance / Net Monthly Burn Rate
Why It Matters
Runway is the most concrete measure of a startup's survival timeline. Every strategic decision should be evaluated against runway: can you afford to experiment with a new channel, hire a VP of Sales, or build a new product line within the time you have? If your runway is 6 months, the answer to most ambitious plans is no.
Runway also dictates fundraising timing. Conventional wisdom says to start fundraising when you have 6-9 months of runway remaining, since raising a round typically takes 3-6 months. Starting too late means negotiating from a position of weakness. Starting too early means spending time fundraising instead of building.
The most dangerous mistake founders make with runway is assuming it is static. Burn rate tends to increase as companies hire and invest. Revenue may not grow as fast as projected. Building in a buffer by assuming pessimistic scenarios keeps companies alive to fight another day.
How to Calculate
Divide total cash and cash equivalents by net monthly burn rate. If you have $2M in the bank and burn $200K per month, your runway is 10 months. For a more accurate projection, model burn rate changes (planned hires, expected revenue growth) month by month rather than assuming a constant burn rate.
Runway Calculator
Cash Balance / Net Monthly Burn Rate
Industry Applications
A SaaS startup with $5M cash and $300K monthly net burn has 16.7 months of runway. After landing a large enterprise deal that adds $80K MRR, net burn drops to $220K, extending runway to 22.7 months.
Benchmark: Best practice is to maintain 18-24 months of runway; below 6 months triggers emergency measures
A DTC ecommerce company extends its runway by 8 months by negotiating 60-day payment terms with suppliers instead of prepaying, improving cash flow without reducing spending.
How to Track in KISSmetrics
Combine cash balance data from your banking and accounting systems with revenue data from KISSmetrics to calculate real-time runway. Update runway calculations monthly and model multiple scenarios: current trajectory, reduced revenue growth, and increased spending for planned initiatives.
Common Mistakes
- -Using a single-month burn rate that might be unusually high or low rather than a 3-month rolling average
- -Not accounting for upcoming large expenses like annual contract renewals, tax payments, or planned hires
- -Assuming revenue will continue growing at current rates without factoring in seasonality or market conditions
- -Counting committed but undisbursed investment funds as cash on hand
Pro Tips
- +Maintain at least 18 months of runway after each funding round to give yourself time to hit milestones
- +Model three runway scenarios: base case, bear case (30% less revenue), and bull case to understand your range of outcomes
- +Begin fundraising with 9 months of runway remaining, not when you are desperate
- +Share runway transparently with your leadership team so everyone understands the constraints and urgency
Related Terms
Burn Rate
Burn rate is the rate at which a company spends its cash reserves, typically measured monthly. Net burn rate accounts for revenue, showing how much cash the company loses per month after income.
Revenue
Revenue is the total income generated by a business from the sale of goods or services before any expenses are deducted. It is the top line of an income statement and the starting point for all financial analysis.
Break-Even Point
The break-even point is the sales volume or revenue level at which total revenue equals total costs, resulting in zero profit or loss. It marks the threshold where a business transitions from losing money to making money.
Monthly Recurring Revenue (MRR)
The predictable revenue a subscription business earns every month from all active subscriptions, normalized to a monthly amount.
Unit Economics
Unit economics is the analysis of revenue and costs associated with a single unit of your business model - typically one customer or one transaction. It reveals whether the fundamental business model is viable at any scale.
See Runway in action
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