Runway is cash on hand divided by net monthly burn. Simple math, high stakes. Here's the version investors actually trust.
Every founder can quote their runway. Few can defend the assumptions behind it. When runway falls under 12 months, investors ask about your assumptions — not the headline number.
Runway (months) = Cash on hand / Net monthly burn. Net burn = gross spend − revenue. Cash on hand should exclude committed-but-unused (like SAFEs not yet closed) and receivables not yet paid.
Base case: current burn, current growth. Bear case: burn holds, growth stalls (no new revenue). Bull case: expansion revenue and pipeline conversion play out. Investors want to see all three, with the assumptions documented.
Some founders quote runway assuming zero revenue drops. That's misleading. Real runway assumes revenue holds only if churn is stable. Model both revenue-holding-flat and revenue-declining scenarios.
Start fundraise conversations at 15-18 months of runway. Formal raise at 12-15 months. Under 6 months you're in a distressed raise and will accept bad terms. Do not let runway drop below 6 months without a signed term sheet.
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