INERSEC
In the startup world, “Burn Rate” is often whispered about with the same mix of reverence and fear as a ghost story told around a campfire. But if you’re a CFO, you know that it shouldn’t be a mystery. It’s simply the speed at which your company is consuming its cash reserves before it starts making enough to cover its own costs.
Think of it as a high-stakes game of musical chairs. The “burn” tells you exactly how much time you have before the music stops and you need to find a seat—usually in the form of a new funding round or, ideally, reaching profitability.
Gross Burn vs. Net Burn: Know the Difference
To manage the burn, you have to understand what’s actually in the fire.
• Gross Burn: This is the total amount of cash leaving your bank account every month. It’s your rent, your AWS bill, and most importantly, your payroll. It doesn’t care if you made a sale or not.
• Net Burn: This is the “true” burn. It’s your Gross Burn minus whatever revenue you brought in. This is the actual hole in your pocket.
If your Gross Burn is $200k but you brought in $50k in revenue, your Net Burn is $150k. That $150k is what determines your survival.
The Runway: Your Most Important Number
As I mentioned in my post on “The Startup CFO”, one of our primary roles is “Translator.” You have to translate that Net Burn into Runway.
Runway = Current Cash Balance / Monthly Net Burn
If you have $1.5M in the bank and your Net Burn is $150k, you have 10 months of runway. That is 10 months to build the product, find the market, or convince an investor that you’re the next big thing. As CFO, you don’t just look at this as a spreadsheet cell; you look at it as the life expectancy of the mission.
Managing the Heat
When the burn gets too high, the instinct is to become the “Department of No.” But a great CFO doesn’t just cut costs; they optimize for velocity. Is that $20k a month in marketing spend increasing our “fuel” (revenue) fast enough to justify the heat? If not, the music is going to stop much sooner than we planned.
Managing burn isn’t about being stingy; it’s about being a steward of time. Because in a startup, cash is time. And once you run out of time, the music stops for everyone.
Question: What’s your “Safety Buffer” for runway? Do you start sweating when you hit 6 months, or are you a “12-month minimum” kind of leader?