Phase 1 · Core Sovereign Layer

Startup Runway Calculator

A frozen cash ÷ burn number lies to you. Model revenue growth against expense creep month by month and see the date your runway truly ends — or whether you're default alive.

How do you calculate startup runway?

Static runway is cash ÷ net monthly burn, where net burn is monthly expenses minus revenue. That assumes burn never changes, so a truer figure simulates each month forward: subtract net burn from cash, then grow revenue and expenses at their own rates, and repeat until cash reaches zero. If revenue overtakes expenses first, you are default alive.

Default alive (Paul Graham’s term) means that on the current trajectory revenue reaches profitability before the cash runs out.
Growing revenue makes dynamic runway longer than cash ÷ burn; expenses growing faster than revenue makes it shorter. The gap is the value of your trajectory.
A common rule of thumb is to raise with 12–18 months of runway left, because a round takes 3–6 months to close.
Under 6 months is the danger zone — you end up negotiating from desperation rather than strength.

Under the hood

The math, fully exposed

We don't freeze your burn. Starting from today, each month is simulated until cash runs out or you reach breakeven:

Static runway = cash ÷ (expenses − revenue)

Each simulated month:
cash = cash − (expenses − revenue)
revenue = revenue × (1 + revenue growth)
expenses = expenses × (1 + expense growth)

Default alive when revenue ≥ expenses before cash ≤ 0

Why simulate: a static number assumes nothing changes. In reality a 8%/mo revenue ramp can add many months of runway — or runaway hiring can erase them. The simulation captures the compounding both ways.
Breakeven beats balance: if revenue growth crosses expenses before zero, you're default alive — the most powerful position a founder can hold in a fundraise.
The danger of expense creep: when expense growth outpaces revenue growth, net burn widens every month and runway collapses faster than the static figure implies.

Your directives

What to do next, based on your numbers

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Answers

Frequently asked questions

How is startup runway actually calculated?

The naive formula is cash ÷ net monthly burn. But that assumes burn is frozen. This tool simulates each month forward: revenue compounds at your growth rate, expenses creep at theirs, and we subtract the changing net burn from cash until it hits zero — or until revenue overtakes expenses and you become "default alive."

What does "default alive" mean?

Coined by Paul Graham: a startup is default alive if, on its current trajectory, revenue growth reaches profitability before the cash runs out. If this calculator shows you crossing breakeven before zero, you control your own destiny and do not strictly need to raise.

How much runway should I have before raising again?

A common rule of thumb is to raise with 12–18 months of runway remaining, because fundraising itself takes 3–6 months and you want to negotiate from strength, not desperation. Under 6 months is a danger zone that weakens your leverage with investors.

Why does my dynamic runway differ from cash ÷ burn?

If your revenue is growing, dynamic runway is longer than the static snapshot because net burn shrinks each month. If your expenses are growing faster than revenue, dynamic runway is shorter. The gap between the two numbers is exactly the value of your growth trajectory.

Open the full Startup Runway calculator on EmpireCalc →