Runway, in Plain Words

Runway is how many months your venture can survive before it must earn or die. It is the first number a professional investor checks and the last number most first-time founders calculate. The formula is embarrassingly simple: money set aside for the venture, divided by what it burns per month.

The discipline is in what you count as burn. Count everything the venture consumes: subscriptions, freelancers, travel, that 'small' software bill — plus the honest value of your time if you have reduced paid work to build it. Founders who count only the obvious costs believe they have eighteen months of runway and hit the wall at ten.

Runway changes behaviour. With twenty months you can afford patient experiments. With six you cannot — you must simplify the offer, chase revenue earlier and cut lovingly-built things that don't sell. Neither situation is bad; flying blind between them is.

Write your runway number where you can see it. Update it monthly. Ventures rarely die of one big blow — they die of nobody watching this number.