Cash Runway Calculator: Months of Cash Left

Cash runway is the number of months your business can keep paying its bills if nothing changes. It is a planning figure, and it is only as good as the three numbers you put in, so use averages from recent months rather than the best or worst one.

Cash on hand today

Average cash coming in each month

Average cash going out each month

Net cash change per month

-3,000

Months of runway

16.7 months

Months of outgoings covered with no income

2.4 months

Cash left after six months

32,000

Net cash change is the money coming in each month minus the money going out. If that number is negative, runway is cash on hand divided by the monthly shortfall, which is how many months the balance lasts if nothing changes. If it is zero or positive, the balance is not shrinking and there is no runway end to report. The outgoings figure divides cash on hand by monthly outflow alone, as if no money came in at all. Use the same currency in all three boxes. Until you change a box, the page shows a worked example of 50,000 on hand, 18,000 in and 21,000 out.

How this works

Subtract monthly cash out from monthly cash in to get the net change. When the net change is negative, divide cash on hand by the size of that monthly shortfall: 50,000 on hand and a 3,000 monthly shortfall gives about 16.7 months. The calculator also shows how many months your outgoings alone would be covered if every sale stopped, and what the balance would be after six months at the current rate.

What it leaves out

The calculator assumes inflows and outflows stay flat. Real months do not. Customers pay late, bills cluster around the start of a quarter, and tax payments, loan repayments and seasonal swings can move the balance well away from a straight line. Use cash in and cash out, not revenue and expenses, since an unpaid invoice is revenue but not cash. It is general information, not financial or tax advice. Take the result to your accountant before you act on it. For the vocabulary, see the accounting terms page, and for how the monthly numbers get checked in the first place, the month-end close checklist.