A cash runway calculator tells you how many months your business can keep operating before it runs out of money at its current rate of spending. You enter your cash on hand and your monthly net burn, the amount of cash you are losing each month after income, and the tool returns your runway in months. The calculation is cash on hand divided by monthly burn, and the result is one of the most important numbers a founder or finance lead can know. Runway sets the clock on every decision, from hiring and marketing to when you need to raise funds or reach break even, and lenders and investors will ask for it early. Knowing it removes guesswork and replaces it with a clear deadline you can plan against. The measure suits startups and growing businesses that are spending more than they earn, but it is equally useful for any business through a tough patch, since it frames how long you have to turn things around. A few habits make it more reliable. Update it monthly using actual figures rather than a stale estimate, because burn changes as you hire or cut back. Use net burn, your outflows less any revenue, not gross spending, so the picture is honest. Leave a safety margin and aim to act well before the runway runs out, since raising money or cutting costs always takes longer than expected. Watch the trend, because rising burn shortens your runway faster than the headline number suggests. Use this tool to test how a cost cut or a revenue lift extends your runway. All figures are in New Zealand dollars and the result is an estimate to support your own planning.
Runway = cash on hand / monthly net burn. At this rate cash reaches zero after the runway period. Estimate only, not financial or tax advice.
The calculator divides your cash on hand by your monthly net burn to find how many months of spending your cash covers. It assumes burn stays steady over the period. If your burn is zero or you are cash flow positive, the runway does not apply because you are not consuming cash.
With $500,000 of cash on hand and a monthly net burn of $40,000, the runway is $500,000 divided by $40,000, which is 12.5 months.
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