Burn Rate
Burn rate describes how quickly a business is using cash over a defined period under a stated gross or net methodology.
Gross burn describes the relevant operating cash outflows for a period. Net burn subtracts relevant realized cash inflows from those outflows over the same period.
Gross burn shows the cost base; net burn includes realized inflow
Keep the period and inclusion rules consistent when comparing either measure.
Cash must have arrived before it offsets cash burn under this method.
What is Burn Rate?
Burn rate describes cash consumption during a defined period. Startups often express it monthly for convenience, but the period can be weekly, quarterly or another interval when the source data and comparison use the same boundary.
Gross burn focuses on the relevant operating cash outflows before realized inflows are considered. Net burn measures the remaining cash consumption after subtracting relevant realized cash inflows for the same period. An issued invoice, recognized revenue or expected collection should not reduce net burn as though the cash had already arrived.
Burn conventions are management measures rather than formal accounting classifications. Teams should document whether taxes, financing costs, capital expenditure, transfers, one-time payments or refunds are included. A cash-flow statement can classify cash under accounting rules, while a burn analysis may use a narrower operating definition for planning.
Gross burn and net burn answer different questions
Gross burn
Shows the selected operating cash outflow and helps a team understand the size and composition of the cost base.
Net burn
Shows how much cash the selected operating activity consumed after relevant realized cash inflows.
Zero or negative net burn
Means realized inflows met or exceeded the included outflows for that period; simple runway division is then not meaningful.
One period may not represent the next
An annual payment can make one month unusually high. A delayed customer receipt can make net burn look worse in one period and better in the next. Hiring, commitments and collection timing can also change the future path.
Use a consistent trailing period or a month-by-month view when that better fits the question. Burn is one input to runway, not a guarantee of how the business will behave.
Why it matters
Burn rate can show the scale of operating cash pressure and help explain why the cash balance changed. The composition matters: payroll, tools, supplier commitments and one-time outflows have different timing and degrees of reversibility.
Review burn beside the current cash position, upcoming obligations and realized inflow. That context helps a team understand which change is structural, which is temporary and which belongs only in a scenario.
Common cash-based convention
Gross burn = Defined operating cash outflows Net burn = Defined operating cash outflows − Relevant realized cash inflows
Illustrative monthly example
A business pays $72,000 in payroll, $8,000 for tools and $12,000 in other included operating outflows. Gross burn is $92,000. It receives $37,000 of relevant customer cash during the same month, so net burn is $55,000. An additional $15,000 invoice that has not been collected does not reduce the month's net burn.
How RunwayCal helps
RunwayCal can keep supported payroll, tools, commitments and realized receipts visible in the financial picture. Runway Overview connects a reviewed burn assumption with cash and runway context. RunwayCal does not assume every revenue record is cash received or automatically decide which burn definition a team should use. The reviewer remains responsible for the selected period and inclusions.
Common mistakes
- 1Subtracting invoiced or expected revenue instead of realized cash inflow.
- 2Comparing burn figures that use different periods or inclusion rules.
- 3Treating one unusual month as the permanent rate that controls runway.
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