Runway is the number every pre-profitability startup tracks to know how long it can operate before running out of cash or needing to raise again.
How it works
Net burn is monthly spend minus monthly revenue. Dividing current cash by that net burn gives the number of months of runway remaining — a company with zero or negative net burn has no runway concern from operations at all.
What this does not include
This assumes a flat, constant burn rate — a real startup’s spend and revenue typically change month to month, so runway calculated this way is a snapshot, not a full cash flow forecast.
How to use this calculator
- Enter current cash, monthly spend, and monthly revenue.
A worked example
$2,000,000 cash on hand, $250,000 monthly spend, $50,000 monthly revenue: net burn = 250,000−50,000 = $200,000/month, runway = 2,000,000 ÷ 200,000 = 10 months.
The same cash and spend, but revenue matching spend exactly at $250,000: net burn = $0 — the company has reached breakeven, so runway becomes effectively indefinite.
What the variables mean
| Variable | Meaning |
|---|---|
| Current cash | Cash reserves on hand |
| Monthly spend | Total monthly expenses |
| Monthly revenue | Total monthly income |
Edge cases worth knowing
Net burn is spend minus revenue, not spend alone. A company with high expenses but matching revenue can have zero net burn despite large gross spending — it’s the gap between the two that actually depletes cash.
Negative cash on hand makes the calculation meaningless, so the calculator declines to show a result for that input.
Frequently asked questions
What’s a healthy amount of runway?
Many investors and operators target at least 12-18 months of runway at any given time, giving enough buffer to fundraise before cash actually runs low.
What’s the difference between gross burn and net burn?
Gross burn is total spend alone; net burn subtracts revenue from that spend — net burn is what actually determines how fast cash depletes.
Does positive net burn mean the company is failing?
Not necessarily — many healthy, well-funded startups deliberately burn cash to grow faster than revenue alone would allow, as long as runway and growth trajectory support it.
