Know exactly when the cash runs out.
Enter your cash, your monthly costs and revenue, and an optional growth rate. See your runway in months, the date the account hits zero, and whether growing revenue gets you to breakeven first.
Your numbers
Net burn is expenses minus revenue. Growth compounds revenue each month, shrinking the burn and extending your runway.
What the runway is telling you
Cash balance over time
Survival scorecard
Month-by-month projection
Revenue compounds by your growth rate each month; expenses stay flat. Net burn is what leaves the bank each month.
| Month | Revenue | Net burn | Cash balance |
|---|
Runway, explained
Runway Math
Cash divided by net burn rate. $500k cash and $40k monthly burn = 12.5 months runway. Update monthly as cash and burn change.
Why 18 Months Is the Target
Fundraising takes 3-6 months. Need 3+ months buffer after closing. Target 18 months at any point to avoid panic fundraising. 12 months is when you START fundraising; 6 months is danger zone.
Runway Extension Tactics
Reduce burn (cut spending). Raise revenue (charge more, sell more). Take bridge financing (convertible note from existing investors). Pause hiring. Strategic furloughs.
Conservative vs Aggressive Runway
Conservative: assume revenue flat or declining. Aggressive: factor expected revenue growth. Both useful, present aggressive to investors, plan conservative internally.
Common questions
When should I start fundraising?
With 9-12 months runway remaining. Less than 9 months = harder negotiating position, potentially down round.
What if my burn rate is increasing?
Use forward-looking burn (next 3 months projection), not historical. Runway shrinks faster than past burn implies.
Does revenue count toward runway?
Net burn already accounts for revenue. If you're profitable, runway is infinite (assuming sustained).
How do I extend runway?
Cut burn first (faster, more controllable). Raise revenue second (slower but builds value). Bridge financing third (dilutive but works).
What's 'default alive' vs 'default dead'?
Paul Graham term: default alive = current revenue trajectory reaches profitability before cash runs out. Default dead = need to raise to survive. Most startups are default dead.
Estimates for planning only. Real runway depends on the timing of cash in and out, one-time costs, hiring plans, and how steady your revenue actually is. Treat growth assumptions conservatively and re-run every month.