How to Calculate Runway (and When to Panic)

Runway in One Sentence

Runway = cash in bank ÷ monthly net burn — how many months until zero if nothing changes.

It's the most important number in an early startup after burn rate. If you're new to the vocabulary, read What Is a Startup? — runway exists because models are unproven.

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The Basic Formula

Runway (months) = Cash balance / Net monthly burn

Net burn = total monthly cash out − monthly cash in (revenue, grants, etc.)

Example: $300k cash, $50k net burn → 6 months runway.

Use gross burn only if revenue is zero or unreliable.

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When to Panic (Honestly)

Runway	Mood	Action
18+ months	Build	Invest in MVP learning
12 months	Plan	Fundraise or path to default alive
6 months	Urgent	Cut burn, close round, or revenue sprint
<3 months	Crisis	Survival mode — tighten burn and revisit fundraising stage

Panic early enough to still have leverage in negotiations.

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What Founders Get Wrong

1. Ignoring hiring lag — offer accepted ≠ cash out same month
2. One-time revenue as runway extension — don't annualize a single deal
3. Static spreadsheet — update weekly in early stage
4. Forggetting unit economics — growth that worsens net burn shrinks runway invisibly

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Extending Runway Without Fundraising

• Delay non-critical hires
• Renegotiate contracts
• Raise prices (Revenue branch thinking)
• Kill low-learning experiments
• Side project income if still part-time

Every month bought is a month to find PMF.

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Runway and Fundraising

Investors ask: "How long does this round last?" Answer with milestones, not vibes:

• Ship X by month 3
• $Y MRR by month 6
• Pre-seed vs seed proof bar for next round

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In Unicorn Rivals

Cash is a visible resource. Upgrades and Disrupt spend feel like runway decisions — especially mid-season when saturation hits.

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Related reading

• Burn Rate Explained
• Unit Economics 101
• 10 First-Year Mistakes

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Feel the clock

Unicorn Rivals — forty founders, one market, no pause button on cash.

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