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Startup Runway & Burn Rate Calculator

Use this free startup runway calculator to see how many months of cash you have left. Enter your cash on hand, monthly expenses, and revenue to find your burn rate, months of runway, and estimated cash-out date.

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7.5 mo
Runway
Cash-Out Date
$40,000
Net Burn / mo
$60,000
Gross Burn / mo
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How to Use This Runway Calculator

  • Cash on Hand — total cash currently in the bank.
  • Monthly Expenses — your total monthly spend (gross burn): payroll, rent, software, marketing, everything.
  • Monthly Revenue — current monthly revenue coming in.
  • Monthly Revenue Growth — optional; if your revenue grows each month, enter the rate to model a more realistic runway.

What Is Runway and Burn Rate?

Burn rate is how fast your company spends cash. Gross burn is your total monthly expenses; net burn is expenses minus revenue — the amount of cash you actually lose each month. Runway is how many months of cash you have left at your current net burn before you hit zero. For a startup, runway is the single most important survival metric: it tells you how much time you have to reach profitability or raise more money.

The classic guidance is to always know your cash-out date and to start fundraising when you have 6–12 months of runway left, because raising money takes longer than founders expect. If your revenue is growing, runway is not a simple division — this calculator models month-by-month growth so your estimate reflects reality, not a static snapshot.

Runway Formula

Net Burn = Monthly Expenses − Monthly Revenue

Runway (months) = Cash on Hand ÷ Net Burn

With revenue growth, runway is calculated by simulating each month: cash + revenue − expenses, with revenue compounding by your growth rate, until cash hits zero.

Example Calculation

A startup has $300,000 in the bank, $60,000 monthly expenses, and $20,000 monthly revenue (no growth):

  • Net burn = $60,000 − $20,000 = $40,000/month
  • Runway = $300,000 ÷ $40,000 = 7.5 months

That means fundraising or a path to profitability needs to be well underway now — not in five months.

Common Mistakes to Avoid

  • Forgetting one-time and annual costs. Annual software renewals or tax bills can blow a hole in runway.
  • Using gross burn instead of net burn. If you have revenue, net burn is the number that determines runway.
  • Assuming flat revenue when it is volatile. Model conservative growth, not best-case.
  • Starting to raise too late. Fundraising typically takes 3–6 months — begin while you still have a comfortable cushion.
  • Ignoring the impact of a new hire. Each hire shortens runway; model it before you sign.

Runway for Startups & Founders

Runway management is the heart of what a fractional CFO does for an early-stage company. It is not just dividing cash by burn — it is building scenario plans (what if we hire two engineers, what if revenue grows 8% a month, what if the raise slips a quarter) so you can make decisions with your eyes open. Investors also expect founders to know these numbers cold.

If your runway is tighter than you would like, the levers are revenue acceleration, cost discipline, and timing your raise well — and a CFO helps you pull them in the right order. If you want a clear, investor-ready runway and burn model for your startup, that is exactly what we build.

Need help interpreting these numbers?

Our Ex-PwC Chartered Accountants help US startups and small businesses turn calculations like this into real financial strategy — pricing, cash flow, fundraising, and growth decisions.

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Frequently Asked Questions

How many months of runway should a startup have?
A common rule of thumb is to maintain at least 6 months of runway at all times, and to start raising your next round when you have 6–12 months left, since fundraising usually takes longer than expected.
What is the difference between gross burn and net burn?
Gross burn is your total monthly cash spend. Net burn is that spend minus your monthly revenue — the actual cash you lose each month. Runway is based on net burn.
How do I calculate my cash-out date?
Divide your cash on hand by your net monthly burn to get months of runway, then add that many months to today. This calculator does it automatically and accounts for revenue growth if you enter a growth rate.
How can I extend my startup's runway?
The main levers are increasing revenue, reducing expenses, and timing your fundraise well. A fractional CFO typically models several scenarios to find the combination that buys the most time without stalling growth.
Does revenue growth change my runway?
Yes, significantly. If revenue grows each month, your net burn shrinks over time and runway extends. This calculator simulates month-by-month growth so your runway reflects that, rather than assuming flat revenue.

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