Startup Runway & Burn Rate Calculator

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

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

How to Calculate Runway (Step by Step)

• Step 1 — Get your cash balance. Total cash across all bank accounts today (include liquid savings, exclude receivables you haven't collected).
• Step 2 — Calculate monthly burn rate. Net burn = total monthly cash out − total monthly cash in. If you spend $60,000 and collect $35,000, your net burn is $25,000/month. Use a 3-month average to smooth one-off spikes.
• Step 3 — Divide. Runway (months) = Cash Balance ÷ Net Monthly Burn. $300,000 ÷ $25,000 = 12 months of runway.
• Step 4 — Mark the cash-out date and start any fundraise 6–9 months before it — raises take longer than founders plan for.

To calculate cash runway with growing revenue, use this calculator's growth input rather than the flat formula — rising collections extend runway in a way a static division can't show.

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.

Frequently Asked Questions

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