The Wren Sessions, a working musician, holds $9,400 in cash against a monthly burn of $2,250, with everything in it: rent, gear, software and the owner draw. That's 4.2 months of runway at the current burn. It's above the four-month line, so the owner can plan in seasons instead of weeks.
Runway = cash on hand ÷ monthly burn, using your heaviest recent burn month rather than your cheapest. The main runway guide has the full reasoning and what to do at each level, and the calculator runs it on your numbers in your browser.
The twist for working musicians
With a $2,250 monthly burn against $9,400 of cash, the demo musician holds about four months, and that's the healthy version of creative income. Irregular earners should target six months, because the gap between paydays is the business model.