Kiln & Co., a ceramics studio selling online, holds $48,300 in cash against a monthly burn of $6,900, everything included: rent, gear, software, and the owner draw. That is 7.0 months of runway at current burn. Above the four-month line, which buys the freedom to think in seasons instead of weeks.
Runway = cash on hand ÷ monthly burn, using your heaviest recent burn month rather than your cheapest. The full reasoning, including what to do at each runway level, lives in the main runway guide; the calculator runs it with your numbers in your browser.
The twist for Etsy sellers and makers
Inventory is cash wearing a costume. A materials buy converts runway into shelf stock, so count planned buys as burn in the month you place them, and remember December revenue lands after December bills.