RightFiguresConstant monthly cash in and cash out
Net burn is monthly cash out minus monthly cash in. The page applies those two amounts once for each month. It does not count calendar days, and it does not say which day a receipt or a payment occurs.
This is not the monthly budget calculator, which reports the dollars left from one month of take-home income. It is not the emergency fund calculator, which divides savings by essential expenses and has no cash inflow. The business break-even calculator counts product units. This page asks how long starting cash lasts when the monthly amounts stay constant.
The SBA glossary describes cash-basis accounting as recording revenue when cash is received and expenses when they are paid in cash. It does not define a runway quotient. The month count here is the constant net outflow applied to the starting cash you enter.
$120,000 of starting cash
$120,000.00 of cash, $10,000.00 in, and $20,000.00 out produce a $10,000.00 net burn. The runway is 12.00 months, exhausted at the end of month 12.
$1,000.00 of cash and $300.00 of cash out, with no cash in, last 3 full months and are exhausted during month 4. $100.00 would remain at the start of that month. The rounded runway is 3.33 months.
A rounded month is not the timing
$1.99 of cash and $2.00 of cash out display a rounded runway of 1.00 months. The remainder is not zero, so cash is exhausted during month 1, with $1.99 at the start of that month. $0.01 of cash against $2.01 of cash out displays 0.00 months and is still exhausted during month 1. The page does not walk month by month. The quotient is the timing.
$0.00 of cash and a positive burn has no runway. Equal cash in and cash out do not change the balance, including when that balance is $0.00. There is no month count.
A surplus has no exhaustion date
$30.00 in and $10.00 out is a $20.00 monthly surplus, including when starting cash is $0.00. $500.00 of cash with $80.00 in and $30.00 out is a $50.00 surplus. The balance grows. The page does not add the surplus into a future balance, and it does not say how much money to raise.
The largest positive-burn case on this page, $100,000,000.00 of cash and $0.01 of net burn, is 10,000,000,000.00 months, exhausted at the end of month 10,000,000,000.
Frequently asked questions
Does 1.00 months mean the cash lasts until the end of month 1?
Only when the remainder is zero. A display of 1.00 months can still be exhausted during month 1 when cash does not divide evenly by the burn.
Does a surplus get an end date?
No. Cash coming in is larger than cash going out, so the page does not name a
month when the balance reaches zero.
Are the amounts sent to analytics?
No. Analytics may record that this calculator ran. The cash amounts and the
runway stay in this browser.
Sources & review
- Glossary of Business Financial Terms — U.S. Small Business Administration
Last reviewed: . The formula is reproduced above so you can check the math independently.
Educational estimate only. This page does not say how much money to raise.