How to Calculate Your Startup Runway (With Free Calculator)

How to Calculate Your Startup Runway (With Free Calculator) Every founder needs to know one number: how long until you run out of money. This is your runway. Get it wrong and you are making decisions in the dark. What Is Runway? Runway is the time you have before cash hits zero. If you have $100,000 in the bank and burn $10,000 per month, your runway is 10 months. Simple math. Critical insight. The Basic Formula Runway = Current Cash / Monthly Burn Rate Your burn rate is everything you spend minus any revenue coming in. For pre-revenue startups, this is just your costs. For those with revenue, subtract it from expenses to get net burn. Why Most Founders Get This Wrong They forget the ramp. Your burn rate today is not your burn rate in six months. If you are hiring, marketing, or building inventory, costs go up. Smart founders model three scenarios: Conservative : Burn stays flat Realistic : Burn grows 10-20% monthly Aggressive : Rapid hiring and marketing spend Each scenario tells a di