SaaS Runway Calculator
Calculate how many months your startup can survive with current cash and burn rate. See scenario projections at different revenue growth rates and know exactly when to start fundraising. Runs entirely in your browser — your numbers stay private.
Scenario Analysis
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How Cash Runway Works for Startups
Cash runway is the number of months a startup can continue operating before it runs out of money. It is calculated by dividing available cash by monthly net burn rate (total expenses minus total revenue). Based on Y Combinator startup guidance and a16z SaaS benchmarks, most VCs expect portfolio companies to maintain 12-18 months of runway. Below 6 months is considered the danger zone where founders lose negotiating leverage and may be forced into unfavorable terms or a distressed sale.
Net Burn Rate vs Gross Burn Rate
Gross burn is total monthly cash outflows (payroll, rent, tools, marketing). Net burn subtracts monthly revenue from gross burn. A company spending $150K/month with $50K in revenue has a gross burn of $150K but a net burn of $100K. Net burn is what actually depletes your bank account and determines true runway. This calculator uses net burn for accurate runway projection, then layers in revenue growth scenarios to show how improving unit economics extends your cash.
When to Start Fundraising
The fundraising process typically takes 3-6 months from first meeting to wire transfer. Y Combinator advises starting when you have at least 6 months of runway remaining — ideally 9-12 months. This gives you leverage to walk away from bad terms. If your runway is under 6 months and you have not started fundraising, you are in a critical position. This calculator shows your fundraising start date so you never miss the window.
Revenue Growth Extends Runway Non-Linearly
Monthly revenue growth dramatically extends runway. A startup with $1M cash and $100K net burn has 10 months at flat revenue. But with 10% monthly revenue growth, that same startup reaches profitability before running out of cash. The scenarios table shows projections at 0%, 10%, and 20% month-over-month growth so you can see the compounding effect. This is why VCs focus on growth rate — it is the single biggest lever for extending runway without additional capital.
Sources: Y Combinator startup guidance, a16z SaaS benchmarks. Last updated: May 2026.