Burn rate and runway calculator
How long the cash lasts at your current burn, and whether revenue growth gets there before the balance does.
Cash-flow positive in
12 months
revenue overtakes costs before the cash runs out
- Net burn today
- $34,000
- Gross burn
- $72,000
- Cash on hand
- $420,000
| Monthly revenue | $38,000 |
|---|---|
| Monthly costs | -$72,000 |
| Net each month | -$34,000 |
- Runway assumes costs stay flat. Hiring or a price rise changes it immediately.
Burning $34,000 a month against $420,000 of cash is 12 months flat — but at 6% monthly growth revenue closes the gap first.
Over the life of it
How this is calculated
Net burn, not gross
Gross burn is what you spend; net burn is spending minus revenue, and it is the one that empties the account. At $72,000 of costs against $38,000 of revenue the net burn is $34,000 a month.
net burn = costs − revenueGrowth is compounded monthly
Revenue grows by the monthly rate each month, so 6% compounds to about 2× in a year rather than 72%. The simulation stops either when cash hits zero or when revenue overtakes costs, whichever comes first.
Worked example: $420,000 in the bank, $34,000 net burn, 6% monthly growth
| Cash | $420,000 |
|---|---|
| Revenue | $38,000 |
| Costs | $72,000 |
| Growth | 6% a month |
| Flat-revenue runway | 12 months |
|---|---|
| With growth | break-even arrives first |
At 6% a month, revenue passes $72,000 in about eleven months — which is why growth rate and runway have to be read together, never separately.
What this assumes
- Costs stay flat while revenue grows.
- Revenue is collected in the month it is earned.
- No further funding arrives.
- Growth continues at the same rate.
Where this commonly goes wrong
- Costs almost never stay flat while revenue doubles — hiring, infrastructure and support all scale, which is why real break-even arrives later than a flat-cost model says.
- Revenue booked is not cash received: 45-day payment terms mean the bank balance lags the revenue line by a month and a half.
- Annual prepaid contracts inflate cash without inflating revenue, which makes runway look longer than it is.
Questions
What is a good runway?
Eighteen to twenty-four months is the common target for a funded company, because raising takes three to six months and you want to raise from strength. Below twelve months, fundraising becomes the main job.
What is the difference between gross and net burn?
Gross burn is total monthly spend. Net burn subtracts revenue and is what actually drains the account. A company spending $72,000 with $38,000 of revenue has a $72,000 gross and $34,000 net burn.
Should runway assume revenue growth?
Show both. The flat-revenue number is the honest floor and the one to plan against; the growth case is the plan. Presenting only the growth case is how companies are surprised by a slow quarter.
How do payment terms affect this?
Directly. On 45-day terms, cash arrives about a month and a half after the revenue is booked, so the bank balance follows a lagged version of the revenue line. Model cash collected, not invoiced.
What is burn multiple?
Net burn divided by net new recurring revenue in the same period. Under 1.5 is considered efficient, over 3 expensive. It answers how much cash it costs to buy a dollar of growth, which runway alone does not.
When should I start cutting costs?
When the runway drops below the time it takes to raise plus a buffer — usually around nine months. Cutting late means cutting deeper, because the savings have fewer months left to accumulate.
Related tools
Sources
This calculator does arithmetic on the figures you enter. It does not account for tax, fees, or your personal circumstances.
T0