Find out how many months your business cash lasts and when it falls below your safety buffer.
Enter the cash you hold today, what comes in and goes out each month, and how you expect both to change. The calculator shows your monthly burn, how many months the cash lasts and the month the balance would go below zero, with a month-by-month table.
| Month | Received | Paid out | Net | Cash at month end |
|---|
The calculator treats every amount as arriving or leaving in the month shown and projects up to 36 months. It does not know about one-off payments, seasonal income or tax due dates; add those to a dated forecast before relying on the result.
How cash runway is calculated
Runway is the number of months your cash lasts at the current rate of spending. The simple version divides cash by net monthly burn: with 60,000 in the bank, 18,000 coming in and 24,000 going out, the burn is 6,000 a month and the cash lasts 10 months. That simple figure ignores change. If receipts grow while costs stay flat, the burn shrinks and the runway stretches; if a large customer pays late, it shortens at once. The table above applies your growth rates month by month, and measures runway to the buffer you want to keep rather than to zero.
A profitable business can still run out of cash when customers pay after the business has paid its own suppliers and staff. Our guide to profit vs cash flow shows how to build the weekly forecast behind these monthly numbers, and currency risk covers income and costs in different currencies.
Questions
What is a good cash runway?
There is no single right number. The runway you need is the time it would take to fix a problem: find new customers, cut costs, raise money or collect overdue invoices. A business that depends on a few large customers, or on funding rounds, needs a longer runway than one with many small, frequent payments.
What is the difference between burn rate and runway?
Burn rate is how much cash the business loses each month: money paid out minus money received. Runway is how long the current cash lasts at that rate. A business with positive net cash flow has no burn and, on these assumptions, no end to its runway.
Should I use invoices or payments received?
Payments received. An invoice that is 60 days from being paid does not help you pay this month's rent. Enter what actually arrives in the bank account.