Burn Rate: What It Is, How to Calculate It, and What VCs Actually Look At

Every VC you pitch will ask about your burn rate. Most founders give the wrong number. Not because they're lying, but because they don't know the difference between gross and net burn. They throw out a number that sounds right, the VC does the math in their head, and suddenly the whole financial picture feels off.

It's one of those things that seems too simple to get wrong. And that's exactly why so many founders get it wrong.

Gross Burn Rate

Total monthly expenses. Period. Salaries, rent, tools, hosting, AWS, that Figma subscription you forgot about. Everything that leaves your bank account in a given month.

If you spend $60K a month, your gross burn is $60K. There's no formula to overthink here. Add up your expenses. That's the number.

Where founders mess this up: they exclude one-time costs, or they use an average from three months ago, or they leave out the contractor they just hired. Your gross burn is what you spent last month. Not what you budgeted. Not what you planned. What actually went out the door.

Net Burn Rate

Gross burn minus revenue. If you spend $60K and bring in $15K, your net burn is $45K. This is the number that determines your runway.

If you have $450K in the bank and your net burn is $45K, you have 10 months of runway. That's it. That's the math that keeps founders up at night.

Net burn is also the number that moves. A good month of sales drops it. A bad hiring decision spikes it. You need to track it monthly, not quarterly. By the time you notice a bad trend in quarterly numbers, you've already lost two months.

Which One Do VCs Care About?

Both. But for different reasons.

Gross burn tells them your cost structure. Are you disciplined with spending? Are you running lean or are you burning through cash on things that don't move the needle? A $40K gross burn with four engineers looks very different from a $40K gross burn with two engineers and a fancy WeWork office.

Net burn tells them how fast you're actually depleting cash. It's the survival number. The one that determines when you run out of money.

If gross and net are identical, you have zero revenue. At pre-seed, nobody cares. At seed, it raises eyebrows. At Series A, it's a problem.

The Implied Burn Rate Trap

Here's one that catches founders off guard. When a VC looks at your round size and your burn, they immediately calculate how many months you're raising for.

$1.5M raise divided by $50K net burn equals 30 months. That's too much. VCs want to see 18 to 24 months of runway from a raise. Enough time to hit your next milestones and raise the next round.

If your math implies 36 or more months, they start wondering whether you're planning to actually grow or just sit on the money. And if it implies 12 months, they wonder why you're not raising more. Either way, the numbers need to tell a story that makes sense.

The fix is simple. Know your planned burn rate for the next 18 months, not just your current one. Show them you have a plan to deploy the capital into growth.

Red Flags VCs Watch For

Burn rate increasing faster than revenue. This is the biggest one. If your expenses grow 30% month over month but revenue grows 5%, the trend line is going in the wrong direction. VCs see this instantly.

Big line items with no clear return. An expensive office before product-market fit. Eight different SaaS tools when you have three people. A head of marketing before you have a repeatable channel. These signal that you're spending to feel like a company rather than spending to become one.

“We'll figure out monetization later” combined with high burn. This works if you're growing users at an insane rate. For everyone else, it's a red flag. VCs have seen too many startups burn through millions chasing growth that never converts to revenue.

And one more: inconsistency between your deck and your actuals. If your pitch deck says $35K burn but your bank statements show $52K, you've just destroyed trust in the first meeting. Know your numbers cold.

Related Reading

Your burn rate only means something in the context of how much runway you have left. And runway is just one of the metrics you should be watching weekly.