Two burn rates, one company: why gross burn and net burn both matter

A preclinical biotech founder we work with was preparing for her Series A. She told the lead investor her monthly burn was $340,000. The investor’s model showed $640,000. Both numbers were correct. She was reporting net burn. The investor was asking about gross burn. Same company, same month, a $300,000 gap, and three weeks of back-and-forth during diligence to sort it out.

The confusion is avoidable. Net burn and gross burn measure different things. Using them interchangeably, especially in investor communications, creates friction that slows down a financing round.

What each number actually measures

Gross burn is the total cash leaving the company each month: payroll and benefits, lab supplies, contract research organization (CRO) payments, facilities, cloud services, and all other operating costs. It is the answer to “what does this company cost to run?”

Net burn subtracts non-dilutive income from that total. Small Business Innovation Research (SBIR) grants, Small Business Technology Transfer (STTR) awards, National Institutes of Health (NIH) contract income, pharmaceutical collaboration payments, and sublicense fees all count as offsets. Net burn is the answer to “how fast is this company consuming the equity capital it raised?”

Neither number is wrong. They answer different questions. The problem comes from using one when the conversation requires the other.

The numbers in this example

The founder was running a ten-person preclinical biotech on an NIH SBIR Phase II award. Here is what the monthly cost structure looked like:

With $4,000,000 in the bank and the SBIR active, net runway was about 11.8 months. Without the SBIR, the gross runway on the same $4,000,000 was about 6.3 months. That is more than one quarter of runway difference, and it depends entirely on whether a single award continues.

Why investors ask for gross burn specifically

Series A investors run detailed models. They ask for gross burn for three specific reasons.

Gross burn is the stress-test number. Non-dilutive income is not permanent. SBIR awards have defined periods of performance. Collaboration payments have milestone schedules. When an investor models the next 18 months, the question is: if every non-dilutive income source stopped today, how long does the company survive on equity alone? That answer requires gross burn, not net.

Upfront collaboration payments distort net burn for months. A biotech that receives a $3,000,000 upfront license payment will show very low or even negative net burn for several months. The gross burn may still be $640,000 per month. The net looks like zero. Investors who see only the net number are reading a picture shaped by deal timing, not by the actual operating cost structure.

Grant periods end at inconvenient times. An SBIR Phase II award has a two-year period of performance. When it ends, the $300,000 monthly offset disappears. Net burn and gross burn converge immediately. A company that has been reporting $340,000 in net burn will report $640,000 in the first full month after the award closes. To any investor who did not know the SBIR was providing the offset, that looks like burn nearly doubled without explanation.

What goes wrong when only one number gets reported

Three problems develop.

Runway planning uses the wrong baseline. A company planning its next financing round based on 11.8 months of net runway may need to begin that process three or more months sooner than expected once the SBIR closes on schedule. The planning gap shows up only after the award ends.

Board oversight is incomplete. Board members need to know what the company costs to run before they can assess whether the team is spending efficiently. If the CFO presents only net burn, and the SBIR ends between meetings, the board sees a number that appears to have nearly doubled with no prior discussion.

Due diligence takes longer. If the books do not cleanly separate gross cash outflow from non-dilutive income offsets, the investor’s finance team has to reconstruct both numbers during diligence. That process takes time and raises questions about the finance function that are hard to walk back once the round is in progress.

What the reporting should look like

For Life Sciences clients we work with, every monthly board package includes both numbers.

The gross burn section lists every cost category: payroll, lab, CRO, facilities, and overhead. Nothing is netted out. It is the complete picture of what the company spends each month.

Below that, a separate section lists every source of non-dilutive income by award or contract, with the expected end date for each. Net burn follows as gross burn minus those offsets.

The runway section shows two scenarios side by side: one assuming all non-dilutive income continues, one assuming it ends on schedule. The gap between those two scenarios is the equity risk the company carries, and it belongs in every board package.

Best practices for biotech burn rate reporting

A few habits that keep this clean and investor-ready:

• Report gross burn and net burn in every board package and investor update. Label both explicitly. Never present a single “burn rate” figure without specifying which one it is.
• List every source of non-dilutive income with its award type and remaining period of performance. Investors need to see when each offset expires.
• Build two runway scenarios in every cash projection: one with all current income, one without. The difference between those scenarios is the risk that needs to be managed before the next raise.
• Track SBIR and STTR award end dates in the financial calendar alongside board meeting dates. A grant that closes two months after a board meeting should be discussed at the meeting before the one where it ends, not after.
• When a pharmaceutical collaboration generates a large upfront payment, exclude it from the run-rate burn calculation. Report gross burn at the steady-state cost structure and treat the upfront as a separate line in the cash position section.

Three questions worth asking

If you are not certain whether your reporting separates these two numbers clearly, three questions to take to whoever manages your finances:

1. In our monthly board package, do we report gross burn and net burn separately, or do we present a single figure without specifying which one it is?
2. For each source of non-dilutive income, what is the remaining period of performance, and what is the plan if it ends without a replacement?
3. What is our gross burn if all grant and contract income stopped today, and how does that change our runway estimate?

If those answers come back uncertain, the current burn rate presentation is probably net only. That is a fixable gap, and worth closing before the next investor conversation.

If you want a second look, send the last three months of financials. We will tell you whether the reporting separates gross and net burn clearly, and whether the runway story holds up under a grant-end stress test.