Startup Runway Calculator

How to use the runway calculator

1. Cash in the bank: enter the money you can actually spend today. Leave out money you have been promised but have not received.
2. Monthly expenses: add up everything you pay in a typical month, such as salaries, rent, software, ads and your own pay.
3. Monthly revenue: enter what customers pay you each month. Use 0 if you are not earning yet.

The result updates as you type. It shows your runway in months, your net monthly burn, the month your cash would run out if nothing changes and the cash you would have left after six months. If you do not know your monthly expenses yet, add them up line by line with the burn rate calculator first.

The runway formula

The part in brackets is your net burn rate. If revenue is equal to or higher than expenses, your cash is not running down and runway is not a limit.

A worked example

Say you have $60,000 saved for the business. You spend $9,000 a month and earn $1,500 a month from your first customers.

Eight months is enough to test an idea, but not much more. After six months at this rate you would have $15,000 left. If you grow revenue to $4,000 a month, net burn falls to $5,000 and runway grows to 12 months.

How to make your runway longer

• Test before you build. The most useful month is one where you learn something without building anything. Validate the idea with interviews and a landing page first.
• Cut costs that do not help you learn. Office space, paid tools you rarely open and early hires are common ones.
• Get paid sooner. Ask for annual plans, deposits or pre-orders.
• Keep your job for longer. Many founders start on the side and only go full time once revenue covers part of their costs.

What the calculator leaves out

This is a simple model. It assumes your expenses and revenue stay the same every month, and it ignores one-off costs, taxes and late payments. It also treats money you have not received yet, such as a promised investment or an unpaid invoice, as if it did not exist. Use it to see where you stand, then build a month-by-month cash flow forecast before you make big decisions. If you have not opened yet, the startup cost calculator shows how much money a chosen number of months would take.