E-Commerce Finance
Cash Flow Runway Calculator
The Cash Flow Runway Calculator projects how many months of cash you have before running out, both at your current burn and accounting for revenue growth. It returns your monthly burn rate, current and projected runway, the month you reach break-even, your cash position at that point, and a month-by-month 12-month projection. The result tells you when you become profitable or when you need to raise.
Who it's for: DTC founders and operators managing a finite cash balance who need to know their runway and when growth turns the business cash-flow positive.
How the Cash Flow Runway Calculator works
You enter your current cash balance, monthly revenue, monthly expenses, and expected monthly growth rate. Monthly burn is expenses minus revenue, and current runway divides your cash by that burn (treated as infinite if you are already profitable).
Projected runway simulates each month forward, growing revenue by your growth rate and adding the resulting profit or loss to cash, stopping when cash hits zero or revenue overtakes expenses. The tool also finds the break-even month (when growing revenue first exceeds expenses) and your cash balance at that moment, which signals whether you make it there without raising.
A 12-month projection table lays out revenue, expenses, profit, and ending cash for each month. The status ranges from critical (under 6 months) to healthy (12 months or more), and recommendations quantify how much a 20 percent burn reduction would extend runway and how much you may need to raise.
The formula
Monthly burn = monthly expenses - monthly revenue. Current runway (months) = current cash / monthly burn (infinite if burn <= 0). Projected runway grows revenue by the monthly growth rate each month and adds profit to cash until it hits zero. Break-even month is the first month where grown revenue exceeds expenses.
Frequently asked questions
What is the difference between current runway and projected runway?+
Current runway assumes revenue stays flat and simply divides your cash by your monthly burn. Projected runway is more realistic because it grows revenue each month by your growth rate, which slows the burn over time and extends runway. If growth is strong enough, projected runway becomes infinite because you reach profitability before the cash runs out.
What should I include in my cash balance?+
Include only liquid cash you can actually spend, such as all business bank and savings accounts. Exclude accounts receivable, inventory, and other non-liquid assets, because runway is about how long your spendable cash lasts. Overstating cash with illiquid assets produces an unrealistically long runway.
How much runway is considered safe?+
The tool treats 18 months or more as healthy, 12 to 18 as good, 6 to 12 as moderate, and under 6 as critical. A common guideline is to start fundraising or cutting costs well before you hit 12 months, because raising capital takes time and negotiating from a position of low runway weakens your terms.
What if my growth rate never reaches break-even?+
If your modeled revenue growth never overtakes expenses, the calculator reports break-even as "Never" and flags that you must either accelerate growth or cut expenses. In that case the recommendations estimate how much cash you would need to raise, since growth alone will not close the gap before you run out.