# How to Calculate Default Alive Runway for Startups > Startup runway spreadsheet shows when cash runs out before profit. - Title: How to Calculate Default Alive Runway for Startups | Shortify - Summary: Startup runway spreadsheet shows when cash runs out before profit. A startup with $600,000 cash, $30,000 monthly revenue, and $90,000 monthly expenses has a… - Keywords: default alive, startup runway, revenue growth, expense growth, cash runway, profitability, committed spend, y combinator, paul graham, startup spreadsheet, Startup Fortune - Source: Startup Fortune — https://startupfortune.com/how-to-calculate-default-alive-runway-for-startups-before-investors-ask - Published: 2026-11-13T20:15:37+00:00 - Read time: 1 min - Topics: default alive, startup runway, revenue growth, expense growth, cash runway, profitability, committed spend, y combinator, paul graham, startup spreadsheet, startups, business ## What is default alive runway? A startup's cash runway without growth or commitments. > A small spreadsheet shows which way, and by how many months ## Naive runway formula fails It ignores growth and commitments, overstating or understating cash. > You can be wrong by months either way ## Startup example with 12% growth A company with $600,000 cash, $30,000 revenue, $90,000 expenses reaches profit in month 12. > Revenue passes expenses in month 12, at about $116,900 against about $114,100 ## 4% growth leads to cash runout Same startup runs out of money in month 10 with 4% monthly revenue growth. > Cash runs out in month 10 ## Committed spend impacts runway Two signed job offers worth $16,000 monthly push profitability from month 12 to 14. > Profitability slips from month 12 to month 14 ## How to build the spreadsheet Six inputs: cash, revenue, expenses, revenue growth, expense growth, committed spend. > That's all. Every extra input makes the answer feel more precise and makes it easier to fool yourself ## Monthly calculations Revenue and expenses grow each month with formulas. > Net is revenue minus expenses. Cash is last month's cash plus net ## Default alive test Cash stays above zero until profitability is reached. > The minimum of the cash column tells you how close you get to zero ## Growth rate accuracy Use actual compound growth rate from last 3-6 months. > If revenue went from $18,000 to $30,000 over six months, the monthly rate is (30,000/18,000)^(1/6)-1, about 8.9% ## Realistic growth rates Most startups have 12% monthly growth, not 4%. > A 7% weekly rate compounds to roughly 34% a month. Most founders reading this aren't near that ## Committed spend details Signed offers, leases, contracts, and cloud services count as committed spend. > An annual contract paid upfront for $36,000 is a $36,000 hit in one month ## Adjusting for reality Split fixed and variable costs to avoid overestimating growth. > Split the lump into fixed costs and variable costs as a percentage of revenue ## Growth decay Growth rates slow over time, so test with declining rates. > Add a column that shrinks the growth rate by 5% each month (multiply the previous month's rate by 0.95) ## Investor use of the model Investors run similar calculations without seeing the spreadsheet. > A founder who arrives with a growth-adjusted runway and a committed-spend schedule has answered the two questions the partner was about to ask ## Key takeaway A startup with $600,000 cash, $30,000 monthly revenue, and $90,000 monthly expenses has a default alive runway of 10 months if revenue grows 12% monthly and expenses rise 2% monthly.