Burn rate is the speed at which a startup spends its cash reserves each month before it reaches profitability. Every pre-revenue or early-revenue company has one, and investors watch it closely. A founder who can't recite their burn rate off the top of their head is almost certainly in trouble.
The term sounds alarming, but knowing your burn rate is simply good financial hygiene. It tells you how long the business can operate without raising more money, which sets the clock on every major decision: hiring, product launches, and fundraising timelines.
Gross burn vs net burn: what's the difference?
There are two versions of burn rate, and confusing them is a common mistake.
Gross burn is the total cash a business spends each month, full stop. If your startup pays $40,000 in salaries, $8,000 in rent, and $12,000 in software and marketing each month, your gross burn is $60,000. It doesn't matter how much revenue you bring in. Gross burn measures outgoings only.
Net burn accounts for revenue. Take that same $60,000 in monthly spend, subtract whatever the business earns in that period, and you have your net burn. If you're bringing in $15,000 a month in subscription revenue, your net burn is $45,000. Net burn is the number that really tells you how fast your cash pile is shrinking.
Founders sometimes lean on gross burn when pitching to investors because a lower-looking net burn figure can obscure how much a business actually costs to run. Investors worth their salt ask for both.
How to calculate your runway
Runway is the amount of time a startup has before it runs out of cash, assuming no additional funding arrives. The formula is straightforward:
Runway (months) = Cash on hand รท Net burn per month
Say your startup has $540,000 in the bank and a net burn of $45,000 per month. That's 12 months of runway. Not comfortable. Most investors advise keeping at least 18 months of runway at all times, because raising a new round typically takes 3 to 6 months, and you don't want to begin that process from a position of desperation.
Runway is closely tied to what investors call the "default alive" or "default dead" question, popularised by venture capitalist Paul Graham. A startup is default alive if, at its current burn rate and growth trajectory, it reaches profitability before the cash runs out. Default dead means it won't, without outside help.
What drives burn rate up?
Headcount is almost always the biggest driver. Salaries, superannuation, and employer taxes can account for 60 to 80 per cent of a startup's monthly spend. A single senior engineering hire in Sydney or Melbourne can add $15,000 to $20,000 per month to your gross burn once on-costs are included.
Beyond salaries, the next largest categories are typically office or co-working space, cloud infrastructure, software licences, and marketing spend. For a startup selling to other businesses, sales team costs and travel can also be significant.
The problem isn't spending per se. It's spending ahead of the signals that justify it. Hiring a sales team of five before product-market fit is confirmed is one of the fastest ways a startup burns through a seed round without building anything durable. Understanding how venture capital works can help founders frame these decisions in terms investors actually use when evaluating risk.
How investors use burn rate to evaluate startups
Burn rate tells a story that revenue figures alone can't. Two startups both generating $1 million in annual recurring revenue can be in very different positions if one has a net burn of $80,000 per month and the other has a net burn of $20,000.
Investors look at burn rate alongside a metric called burn multiple: how many dollars the startup burns for every dollar of new net revenue it adds. A burn multiple below 1.5 is generally considered efficient. Above 2 raises eyebrows. Above 3 means the business is spending far more to grow than the growth justifies.
During the funding boom of 2021 and 2022, many startups ran burn multiples above 5 without consequence because capital was cheap and growth was prized above all else. The rate environment that followed forced a reckoning, and burn discipline became a competitive advantage overnight. Founders who'd always kept burn tight suddenly found investors far more interested in their businesses than in higher-spending peers. This connects directly to the fundamentals of cash flow, which determine whether a business can actually service its obligations as spending outpaces revenue.
What's an acceptable burn rate?
There's no universal answer. A pre-revenue startup in the biotech sector might sustain $500,000 a month in burn because the timeline to a product is long and the upside is enormous. A SaaS startup at the same burn level with $50,000 in monthly revenue would concern most investors.
Context matters: stage, sector, market size, and the quality of the team's previous capital allocation all factor in. What investors reliably dislike is a founder who doesn't know their numbers. Not knowing your net burn to the nearest $5,000, or not being able to state your runway in months, signals operational immaturity that's hard to overlook.
A useful discipline is calculating burn rate weekly, not monthly. Monthly reviews mean a surprise can sit undetected for 30 days. Weekly tracking catches spending drift early, when it's still reversible.
Reducing burn without killing the business
When founders need to cut burn, headcount reductions get the most attention, but they're rarely the first move a disciplined operator makes. Software subscriptions, unused cloud capacity, contractor agreements, and office costs are typically faster to adjust and less damaging to culture.
Renegotiating vendor contracts is another lever that founders underuse. Suppliers would generally rather cut their margin than lose a customer entirely, especially if that customer is growing. A single conversation with a cloud provider or a payroll software vendor can knock thousands off monthly spend without any operational disruption.
The goal isn't to run the business on the absolute minimum. It's to spend at a rate that's honest about where the company actually is, rather than where founders hope it will be in 18 months. Burn rate is ultimately a discipline tool. The startups that get it right are the ones that treat every dollar of runway as time bought to prove the next thing worth proving.