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Every business is a countdown clock. Know your number.
Runway is the only startup metric that is literally survival: months until cash hits zero. This calculator simulates it honestly — expenses against revenue that compounds at your growth rate — and shows both the optimistic case and the zero-growth case investors will ask for.
Founders and small business owners run it monthly — it is the survival countdown. The zero-growth case is the floor investors and lenders ask for, and having both numbers in seconds beats a spreadsheet nobody updates.
Three to six months of expenses is the standard buffer for established businesses; pre-profit startups raising money want 12–18 months so a fundraise never happens from desperation. If runway is shrinking, the only three fixes are more revenue, less burn, or more capital — the math shows which lever matters most.
Burn rate is the monthly net cash loss (expenses − revenue); runway is cash ÷ burn. Both lie if revenue is growing fast — compounding shortens burn over time, which is why this calculator simulates month by month instead of dividing once.
Cut burn before chasing revenue — cost cuts take effect this month, revenue takes effect next quarter. Founders also systematically overestimate growth; plan to the 0% case and treat any growth as margin of safety.