Calculate your startup's runway with scenario modeling, revenue growth projections, and fundraising requirements. Plan your path to profitability or your next fundraise.
REVENUE MODELING
Formula:
Runway = Cash / (Burn - Revenue)
Enter your cash balance and burn rate
Add revenue for growth projections
Startup runway is the number of months a company can continue operating before exhausting its cash reserves. It is calculated by dividing current cash by monthly net burn rate (total expenses minus revenue). The industry standard is 18-24 months of post-funding runway, giving founders adequate time to hit milestones and raise the next round.
Runway directly ties to burn rate, which measures how quickly a company consumes cash. Seed-stage startups typically burn $75K-$100K per month, while Series A companies burn $200K-$500K per month. A seed startup with $2M in the bank and $80K net burn has 25 months of runway, comfortably above the 18-month minimum. Track your monthly recurring revenue with the MRR calculator to understand how revenue offsets burn.
The median time from seed to Series A has stretched to over 20 months as of 2025, up from roughly 15 months in 2019. This 47% increase means founders need longer runway than ever. In favorable funding environments 18 months may suffice, but during downturns 24-30 months provides necessary safety margin. Companies that begin fundraising with 9+ months remaining receive valuations roughly 20% higher than those starting at 6 months.
Revenue growth fundamentally changes runway calculations. A startup generating growing ARR will see its net burn decrease over time, extending runway well beyond simple cash-divided-by-burn projections. This is why sophisticated runway modeling uses multiple scenarios with different growth assumptions. Use the churn rate calculator alongside this tool to stress-test your revenue retention assumptions.
Basic Runway = Current Cash / Net Burn Rate
Where Net Burn Rate equals:
Net Burn = Monthly Expenses - Monthly Revenue
Sum all liquid assets including bank accounts, money market funds, and any short-term investments that can be converted to cash within 30 days. This is your starting runway base.
Add all recurring monthly expenses: salaries, benefits, rent, software subscriptions, marketing spend, hosting costs, legal and accounting fees. Be comprehensive and include quarterly or annual expenses divided into monthly equivalents.
Calculate your actual monthly revenue using your MRR calculator. Subtract this from gross burn to get net burn. If net burn is negative, you are cash flow positive and technically have infinite runway.
Project how revenue will change over time. Conservative scenarios assume current growth rates decline, moderate scenarios maintain current trajectories, and aggressive scenarios project acceleration. Each scenario produces different runway projections.
Based on your chosen scenario, calculate the specific month when cash reserves will be exhausted. This date is critical for planning fundraising timelines, as you should begin raising 6-9 months before this point.
While runway and burn rate are closely related, they measure fundamentally different aspects of startup financial health. Understanding this distinction is crucial for making informed decisions about growth strategy and fundraising timing.
A startup can have high burn rate but long runway (well-capitalized), or low burn rate but short runway (underfunded). The optimal combination depends on market opportunity, competitive dynamics, and fundraising environment. Use a burn rate model to analyze your monthly cash consumption in detail.
A B2B SaaS company raised a $2.5M seed round. Current MRR is $25K growing 15% monthly. Monthly burn is $100K (3 engineers, 1 sales rep, cloud hosting, office).
With 15% monthly MRR growth, this startup reaches breakeven around month 16 when revenue surpasses expenses. Since the median seed-to-Series-A gap is now 20+ months, 33 months of basic runway provides strong buffer. They can afford to invest in growth and begin Series A preparation around month 12. Track revenue trajectory with the MRR calculator.
A fintech company raised a $12M Series A (median Series A round in 2025-2026). Current MRR is $150K, monthly burn is $400K including heavy engineering and compliance spend.
Strong 48-month runway, but this company plans to hire aggressively, which will increase burn to $600K per month within 6 months. Adjusted runway: $12M / ($600K - $200K projected MRR) = 30 months. The key metric to watch is whether CAC payback improves with scale and whether LTV justifies the acquisition cost.
A bootstrapped company has $200K in savings, $80K MRR, and currently spends $70K monthly, making it slightly profitable.
This company has infinite runway and is growing organically. If they raise venture capital to accelerate growth, they should model how increased burn rate affects runway. Calculate potential ownership changes with the dilution calculator and model the full cap structure using the cap table calculator before deciding whether the growth acceleration justifies the equity trade-off.
The baseline runway target for any venture-backed startup is 18 months at minimum. Top-performing companies target 24 months to allow room for pivots, market shifts, and the increasingly long fundraising timelines of 2025-2026. Seed-stage startups should plan for 18-24 months; Series A for 24 months; deep-tech and hardware for 24+ months.
| Stage | Median Burn | Target Runway | Time to Next Round |
|---|---|---|---|
| Pre-Seed | $10K-$25K/mo | 12-18 months | 6-12 months |
| Seed | $75K-$100K/mo | 18-24 months | 20+ months |
| Series A | $200K-$500K/mo | 24 months | 18-24 months |
| Series B+ | $500K-$1M+/mo | 24+ months | 18-24 months |
Burn rate data from Brex and Carta 2025 reports. Seed-to-Series-A timing from Carta Q2 2025. Deep-tech and hardware startups should add 20-30% buffer above these targets.
Focus on MVP and initial traction
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Scale repeatable growth engine
Accelerate market dominance
While runway calculations are essential for financial planning, they have inherent limitations that founders and investors should understand when making strategic decisions.
Basic runway calculations assume constant monthly burn. In reality, expenses fluctuate due to hiring spikes, one-time costs, seasonal marketing spend, and infrastructure investments. Build buffer for unpredictable expenses.
Projecting future revenue growth is inherently uncertain. External factors like economic conditions, competitive dynamics, and market shifts can dramatically impact growth rates. Model multiple scenarios rather than relying on single projections.
Runway calculations do not account for the fact that fundraising becomes harder as runway decreases. Investors prefer companies with 12+ months runway, creating a cliff effect where options narrow rapidly below certain thresholds.
Revenue recognition and cash collection are not the same. Enterprise SaaS companies often have 30-90 day payment terms, meaning booked revenue may not convert to cash for months. Track actual cash collections separately.
Simple runway metrics do not show what costs are variable versus fixed, or how quickly a company could cut burn if needed. Understanding expense flexibility is as important as knowing current runway.
For more guidance, visit the Planning tools hub.
For fundraising benchmarks and runway targets, visit the Startup tools hub.
Pair this tool with the CAC calculator and LTV calculator to validate unit economics alongside runway. Model equity impact with the dilution calculator and vesting schedule tool.
Target 18-24 months runway post-funding. The median seed-to-Series A gap is now 20+ months, so anything under 18 months creates dangerous fundraising pressure and weakens your negotiating position.
Start fundraising with 9-12 months runway remaining. Series A rounds take a median of 4 months to close, and companies that begin their raise early receive roughly 20% higher valuations than those waiting until 6 months remain.
Model multiple scenarios. Revenue growth dramatically extends runway: a seed startup with 15% monthly MRR growth can reach breakeven in 14-16 months, turning finite runway into indefinite sustainability. Use MRR and churn calculators to validate growth assumptions.
Know your cost levers. Each new hire adds $8K-$20K per month in fully-loaded cost. Even moving from $0 to $50K MRR at $200K monthly burn adds over 3 months of runway. Model different hiring plans with the burn rate calculator before committing.
CB Insights data shows running out of capital is the immediate cause of failure for 70% of VC-backed shutdowns since 2023. Track runway weekly, maintain contingency plans, and explore options like venture debt or funding scenarios before they are urgently needed.